A search is presented for flavour-changing neutral-current interactions involving the top quark, the Higgs boson and an up-type quark ($q=u,c$) with the ATLAS detector at the Large Hadron Collider. The analysis considers leptonic decays of the top quark along with Higgs boson decays into two $W$ bosons, two $Z$ bosons or a $\tau^{+}\tau^{-}$ pair. It focuses on final states containing either two leptons (electrons or muons) of the same charge or three leptons. The considered processes are $t\bar{t}$ and $Ht$ production. For the $t\bar{t}$ production, one top quark decays via $t\to Hq$. The proton-proton collision data set analysed amounts to 140 fb$^{-1}$ at $\sqrt{s}=13$ TeV. No significant excess beyond Standard Model expectations is observed and upper limits are set on the $t\to Hq$ branching ratios at 95% confidence level, amounting to observed (expected) limits of $\mathcal{B}(t\to Hu)<2.8\,(3.0) \times 10^{-4}$ and $\mathcal{B}(t\to Hc)<3.3\,(3.8) \times 10^{-4}$. Combining this search with other searches for $tHq$ flavour-changing neutral-current interactions previously conducted by ATLAS, considering $H\to b\bar{b}$ and $H\to\gamma\gamma$ decays, as well as $H\to\tau^{+}\tau^{-}$ decays with one or two hadronically decaying $\tau$-leptons, yields observed (expected) upper limits on the branching ratios of $\mathcal{B}(t\to Hu)<2.6\,(1.8) \times 10^{-4}$ and $\mathcal{B}(t\to Hc)<3.4\,(2.3) \times 10^{-4}$.
Pre-fit background composition of the SR$2\ell$ Dec. The table shows the event yields as opposed to just the percentages of the relevant background processes.
Pre-fit background composition of the SR$2\ell$ Prod. The table shows the event yields as opposed to just the percentages of the relevant background processes.
Pre-fit background composition of the SR$3\ell$ Dec. The table shows the event yields as opposed to just the percentages of the relevant background processes.
Searches for the exclusive decays of the Higgs boson into $D^*\gamma$ and of the $Z$ boson into $D^0\gamma$ and $K^0_s\gamma$ can probe flavour-violating Higgs and $Z$ boson couplings to light quarks. Searches for these decays are performed with a $pp$ collision data sample corresponding to an integrated luminosity of $136.3$ fb$^{-1}$ collected at $\sqrt{s}=13$ TeV between 2016-2018 with the ATLAS detector at the CERN Large Hadron Collider. In the $D^*\gamma$ and $D^0\gamma$ channels, the observed (expected) 95$\%$ confidence-level upper limits on the respective branching fractions are ${\cal B}(H\rightarrow D^*\gamma)< 1.0 (1.2)\times 10^{-3}$, ${\cal B}(Z\rightarrow D^0\gamma)< 4.0 (3.4)\times 10^{-6}$, while the corresponding results in the $K^0_s\gamma$ channel are ${\cal B}(Z\rightarrow K^0_s\gamma)< 3.1 (3.0)\times 10^{-6}$.
Numbers of observed and expected background events for the $m_{\mathcal{M}\gamma}$ ranges of interest. Each expected background and the corresponding uncertainty is obtained by integrating the total pdf after a background-only fit to the data, where the uncertainty does not take into account statistical fluctuations in each mass range. Expected Higgs and $Z$ boson signal contributions, with their corresponding total systematic uncertainty, are shown for reference branching fractions of $10^{-3}$ and $10^{-6}$, respectively. Entries are marked with a dash when there is no signal of that type in the specified range.
Observed and expected (with the corresponding $\pm1\sigma$ intervals) 95% CL upper limits on the branching fractions for $H\rightarrow D^*\gamma$, $Z\rightarrow D^0\gamma$ and $Z\rightarrow K^0_s\gamma$. Standard Model production of the Higgs boson is assumed. The corresponding upper limits on the production cross-section times branching fraction $\sigma\times\mathcal{B}$ are also shown.
A search for a new $Z'$ gauge boson predicted by $L_{\mu}-L_{\tau}$ models, based on charged-current Drell-Yan production, $pp \rightarrow W^{\pm(*)} \rightarrow Z' \mu^{\pm} \nu \rightarrow \mu^{\pm}\mu^{\mp}\mu^{\pm}\nu$, is presented. The data sample used corresponds to an integrated luminosity of 140 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} = 13$ TeV recorded by the ATLAS detector at the Large Hadron Collider. The search examines a final state of $3\mu$ plus large missing transverse momentum. Upper limits are set on the $Z'$ production cross-section times branching ratio in the mass range of 5-81 GeV. After combining with the previous $Z'$ search using the neutral-current Drell-Yan production with a $4\mu$ final state, the most stringent exclusion limits to date are achieved in the parameter space of the $Z'$ coupling strength and mass.
Observed and expected upper limits at 95% CL on the production cross-section times branching fraction of the process $pp\to W\to Z^{\prime}$ $\mu \nu \to \mu \mu \mu \nu$ as a function of $m_{Z^{\prime}}$.
Observed and expected upper limits at 95% CL on the coupling parameter $g_{Z^{\prime}}$ as a function of $m_{Z^{\prime}}$ from the statistical combination of the $3\mu$ and $4\mu$ channels.
Exclusion contour compared to the limits from the Neutrino Trident and the $B_{S}$ mixing experimental results.
Statistical combinations of searches for charginos and neutralinos using various decay channels are performed using $139\,$fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=13\,$TeV with the ATLAS detector at the Large Hadron Collider. Searches targeting pure-wino chargino pair production, pure-wino chargino-neutralino production, or higgsino production decaying via Standard Model $W$, $Z$, or $h$ bosons are combined to extend the mass reach to the produced SUSY particles by 30-100 GeV. The depth of the sensitivity of the original searches is also improved by the combinations, lowering the 95% CL cross-section upper limits by 15%-40%.
Expected 95% CL exclusion limits on the simplified models of chargino-pair production decaying via W bosons.
$+1\sigma$ expected 95% CL exclusion limits on the simplified models of chargino-pair production decaying via W bosons.
$-1\sigma$ expected 95% CL exclusion limits on the simplified models of chargino-pair production decaying via W bosons.
A summary of the constraints from searches performed by the ATLAS Collaboration for the electroweak production of charginos and neutralinos is presented. Results from eight separate ATLAS searches are considered, each using 140 fb$^{-1}$ of proton-proton data at a centre-of-mass energy of $\sqrt{s}$=13 TeV collected at the Large Hadron Collider during its second data-taking run. The results are interpreted in the context of the 19-parameter phenomenological minimal supersymmetric standard model, where R-parity conservation is assumed and the lightest supersymmetric particle is assumed to be the lightest neutralino. Constraints from previous electroweak, flavour and dark matter related measurements are also considered. The results are presented in terms of constraints on supersymmetric particle masses and are compared with limits from simplified models. Also shown is the impact of ATLAS searches on parameters such as the dark matter relic density and the spin-dependent and spin-independent scattering cross-sections targeted by direct dark matter detection experiments. The Higgs boson and Z boson `funnel regions', where a low-mass neutralino would not oversaturate the dark matter relic abundance, are almost completely excluded by the considered constraints. Example spectra for non-excluded supersymmetric models with light charginos and neutralinos are also presented.
SLHA files and exclusion information (in CSV format) are available to download for the pMSSM models in this paper. Please refer to <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2020-15/inputs/ATLAS_EW_pMSSM_Run2.html">this web page</a> for download links along with a description of the contents.
SLHA files and exclusion information (in CSV format) are available to download for the pMSSM models in this paper. Please refer to <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2020-15/inputs/ATLAS_EW_pMSSM_Run2.html">this web page</a> for download links along with a description of the contents.
This paper presents a search for pair production of higgsinos, the supersymmetric partners of the Higgs bosons, in scenarios with gauge-mediated supersymmetry breaking. Each higgsino is assumed to decay into a Higgs boson and a nearly massless gravitino. The search targets events where each Higgs boson decays into $b\bar{b}$, leading to a reconstructed final state with at least three energetic $b$-jets and missing transverse momentum. Two complementary analysis channels are used, with each channel specifically targeting either low or high values of the higgsino mass. The low-mass (high-mass) channel exploits 126 (139) fb$^{-1}$ of $\sqrt{s}=13$ TeV data collected by the ATLAS detector during Run 2 of the Large Hadron Collider. No significant excess above the Standard Model prediction is found. At 95% confidence level, masses between 130 GeV and 940 GeV are excluded for higgsinos decaying exclusively into Higgs bosons and gravitinos. Exclusion limits as a function of the higgsino decay branching ratio to a Higgs boson are also reported.
Post-fit SR yields of the high-mass channel. The upper panel shows the observed number of events, as well the post-fit background predictions in each region. The bottom panel shows the ratio of the observed data and the total background prediction. The shaded areas correspond to the total statistical and systematic uncertainties obtained after the fit and described in Section 6.
Post-fit SR yields of the high-mass channel. The upper panel shows the observed number of events, as well the post-fit background predictions in each region. The bottom panel shows the ratio of the observed data and the total background prediction. The shaded areas correspond to the total statistical and systematic uncertainties obtained after the fit and described in Section 6.
Post-fit SR yields of the high-mass channel. The upper panel shows the observed number of events, as well the post-fit background predictions in each region. The bottom panel shows the ratio of the observed data and the total background prediction. The shaded areas correspond to the total statistical and systematic uncertainties obtained after the fit and described in Section 6.
Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass-splitting is $\mathcal{O}$(1 GeV). This Letter presents a novel search for nearly mass-degenerate higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass-splittings between the lightest charged and neutral higgsinos from 0.3 GeV to 0.9 GeV is excluded at 95% confidence level, with a maximum reach of approximately 170 GeV in the higgsino mass.
Number of expected and observed data events in the SR (top), and the model-independent upper limits obtained from their consistency (bottom). The symbol $\tau_{\ell}$ ($\tau_{h}$) refers to fully-leptonic (hadron-involved) tau decays. The Others category includes contributions from minor background processes including $t\bar{t}$, single-top and diboson. The individual uncertainties can be correlated and do not necessarily sum up in quadrature to the total uncertainty. The bottom section shows the observed 95% CL upper limits on the visible cross-section ($\langle\epsilon\sigma\rangle_{\mathrm{obs}}^{95}$), on the number of generic signal events ($S_{\mathrm{obs}}^{95}$) as well as the expected limit ($S_{\mathrm{exp}}^{95}$) given the expected number (and $\pm 1\sigma$ deviations from the expectation) of background events.
Expected (dashed black line) and observed (solid red line) 95% CL exclusion limits on the higgsino simplified model being considered. These are shown with $\pm 1\sigma_{\mathrm{exp}}$ (yellow band) from experimental systematic and statistical uncertainties, and with $\pm 1\sigma_{\mathrm{theory}}^{\mathrm{SUSY}}$ (red dotted lines) from signal cross-section uncertainties, respectively. The limits set by the latest ATLAS searches using the soft lepton and disappearing track signatures are illustrated by the blue and green regions, respectively, while the limit imposed by the LEP experiments is shown in gray. The dot-dashed gray line indicates the predicted mass-splitting for the pure higgsino scenario.
Expected (dashed black line) and observed (solid red line) 95% CL exclusion limits on the higgsino simplified model being considered. These are shown with $\pm 1\sigma_{\mathrm{exp}}$ (yellow band) from experimental systematic and statistical uncertainties, and with $\pm 1\sigma_{\mathrm{theory}}^{\mathrm{SUSY}}$ (red dotted lines) from signal cross-section uncertainties, respectively. The limits set by the latest ATLAS searches using the soft lepton and disappearing track signatures are illustrated by the blue and green regions, respectively, while the limit imposed by the LEP experiments is shown in gray. The dot-dashed gray line indicates the predicted mass-splitting for the pure higgsino scenario.
A search for a new heavy boson produced via gluon-fusion in the four-lepton channel with missing transverse momentum or jets is performed. The search uses proton-proton collision data equivalent to an integrated luminosity of 139 fb$^{-1}$ at a centre-of-mass energy of 13 TeV collected by the ATLAS detector between 2015 and 2018 at the Large Hadron Collider. This study explores the decays of heavy bosons: $R\rightarrow SH$ and $A\rightarrow ZH$, where $R$ is a CP-even boson, $A$ is a CP-odd boson, $H$ is a CP-even boson, and $S$ is considered to decay into invisible particles that are candidates for dark matter. In these processes, $S\rightarrow \textrm{invisible}$ and $H\rightarrow ZZ$. The $Z$ boson associated with the heavy scalar boson $H$ decays into all decay channels of the $Z$ boson. The mass range under consideration is 390-1300 (320-1300) GeV for the $R$ ($A$) boson and 220-1000 GeV for the $H$ boson. No significant deviation from the Standard Model backgrounds is observed. The results are interpreted as upper limits at a 95% confidence level on the cross-section times the branching ratio of the heavy resonances.
Observed and expected distributions of the invariant mass of the four-lepton system in the $R\to SH\to 4\ell+E^{\textrm{miss}}_{\textrm{T}}$ search for SR1 under a background-only fit to data. The total background includes the $q\overline{q}\to ZZ$, $gg\to ZZ$, $q\overline{q}\to ZZ$ (EW), $VVV$, $t\overline{t}V$, $t\overline{t}$, $Z$+jets and $WZ$ processes. The distribution of the $(m_{R}, m_{H}) = (500, 300)$ GeV signal is normalised to the observed upper limit on the cross-section (25.0 fb).
Observed and expected distributions of the invariant mass of the four-lepton system in the $R\to SH\to 4\ell+E^{\textrm{miss}}_{\textrm{T}}$ search for SR2 under a background-only fit to data. The total background includes the $q\overline{q}\to ZZ$, $gg\to ZZ$, $q\overline{q}\to ZZ$ (EW), $VVV$, $t\overline{t}V$, $t\overline{t}$, $Z$+jets and $WZ$ processes. The distribution of the $(m_{R}, m_{H}) = (500, 300)$ GeV signal is normalised to the observed upper limit on the cross-section (25.0 fb).
Observed and expected distributions of the invariant mass of the four-lepton system in the $R\to SH\to 4\ell+E^{\textrm{miss}}_{\textrm{T}}$ search for SR3 under a background-only fit to data. The total background includes the $q\overline{q}\to ZZ$, $gg\to ZZ$, $q\overline{q}\to ZZ$ (EW), $VVV$, $t\overline{t}V$, $t\overline{t}$, $Z$+jets and $WZ$ processes. The distribution of the $(m_{R}, m_{H}) = (500, 300)$ GeV signal is normalised to the observed upper limit on the cross-section (25.0 fb).
Presented is the search for anomalous Higgs boson decays into two axion-like particles (ALPs) using the full Run 2 data set of 140 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS experiment. The ALPs are assumed to decay into two photons, providing sensitivity to recently proposed models that could explain the $(g-2)_\mu$ discrepancy. This analysis covers an ALP mass range from 100 MeV to 62 GeV and ALP-photon couplings in the range $10^{-5}\, \text{TeV}^{-1}<C_{a\gamma\gamma}/\Lambda<1\, \text{TeV}^{-1}$, and therefore includes signatures with significantly displaced vertices and highly collinear photons. No significant excess of events above the Standard Model background is observed. Upper limits at 95% confidence level are placed on the branching ratio of the Higgs boson to two ALPs in the four-photon final state, and are in the range of $ 10^{-5}$ to $3\times 10^{-2}$, depending on the hypothesized ALP mass and ALP-photon coupling strength.
Cut-flow and number of events in a region with $110 \text{ GeV} <m_{aa}<130 \text{ GeV}$ for selected signal samples
Overview of relative systematic uncertainties on the signal normalization for selected couplings and mass points in the dominant categories. All photon related uncertainties are summarized under "standard photon", while all customised photon related uncertainties (e.g. displaced photons, NN-based photon IDs) are summarized under "custom photon".
Upper limits on $\mathcal{B}(H\rightarrow aa\rightarrow 4\gamma)$ at 95% CL as a function of the axion mass and for ALP-photon coupling $C_{a\gamma\gamma}=1$.
A search is reported for long-lived dark photons with masses between 0.1 GeV and 15 GeV, from exotic decays of Higgs bosons produced via vector-boson-fusion. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are probed. This search uses the full LHC Run 2 (2015-2018) data sample collected in proton-proton collisions at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 139 $fb^{-1}$. Dominant backgrounds from Standard Model processes and non-collision sources are estimated by using data-driven techniques. The observed event yields in the signal regions are consistent with the expected background. Upper limits on the Higgs boson to dark photon branching fraction are reported as a function of the dark-photon mean proper decay length or of the dark-photon mass and the coupling between the Standard Model and the potential dark sector. This search is combined with previous ATLAS searches obtained in the gluon-gluon fusion and \textit{WH} production modes. A branching fraction above 10% is excluded at 95% CL for a 125 GeV Higgs boson decaying into two dark photons for dark-photon mean proper decay lengths between 173 and 1296 mm and mass of 10 GeV.
Observed 95% CL upper limits on B(H→ 2γ<sub>d</sub>+X) for different γ<sub>d</sub> masses and a 125 GeV Higgs boson, as a function of the dark-photon mean proper decay length cτ. The limits are shown for the SR<sub>μ</sub> search channel, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio is larger than unity.
Observed 95% CL upper limits on B(H→ 2γ<sub>d</sub>+X) for different γ<sub>d</sub> masses and a 125 GeV Higgs boson, as a function of the dark-photon mean proper decay length cτ. The limits are shown for the SR<sub>c</sub><sup>L</sup> search channel, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio is larger than unity.
Observed 95% CL upper limits on B(H→ 2γ<sub>d</sub>+X) for different γ<sub>d</sub> masses and a 125 GeV Higgs boson, as a function of the dark-photon mean proper decay length cτ. The limits are shown for the SR<sub>c</sub><sup>H</sup> search channel, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio is larger than unity.
A combination of searches for resonant Higgs boson pair production is presented, using up to 139 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: $b\bar{b}b\bar{b}$, $bb\tau^+\tau^-$ and $bb\gamma\gamma$. No excess above the expected background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV-5 TeV. The observed (expected) limits are in the range 0.96-600 fb (1.2-390 fb). The limits are interpreted in the Type-I Two-Higgs-Doublet Model and the Minimimal Supersymmetric Standard Model, and constrain parameter space not previously excluded by other searches.
Local p-value as a function of the resonance mass $m_{X}$. Some table entries are empty because resonance masses from 251 GeV to 5 TeV are considered, whereas some channels only use masses in a certain, more restricted, range.
Observed significance as a function of the resonance $m_{X}$. Some table entries are empty because resonance masses from 251 GeV to 5 TeV are considered, whereas some channels only use masses in a certain, more restricted, range.
Observed and expected upper limits at the 95% CL on the resonant Higgs boson pair production cross section as a function of the resonance mass $m_{X}$. Some table entries are empty because resonance masses from 251 GeV to 5 TeV are considered, whereas some channels only use masses in a certain, more restricted, range.
This paper reports cross-section measurements of $ZZ$ production in $pp$ collisions at $\sqrt{s}=13.6$ TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb$^-1$. Events in the $ZZ\rightarrow4\ell$ ($\ell = e$, $\mu$) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 $< m_Z <$ 116 GeV for both $Z$ bosons, yielding $16.8 \pm 1.1$ pb. The results are well described by the Standard Model predictions.
The measured differential cross-sections compared to the predictions in the $m_{4\ell}$ bins
The measured differential cross-sections compared to the predictions in the $p_T^{4\ell}$ bins
This paper presents a search for a new $Z^\prime$ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back as Standard Model particles. This analysis is based on proton-proton collision data recorded at $\sqrt{s}=13$ TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb$^{-1}$. After selecting events containing large-radius jets with high track multiplicity, the invariant mass distribution of the two highest-transverse-momentum jets is scanned to look for an excess above a data-driven estimate of the Standard Model multijet background. No significant excess of events is observed and the results are thus used to set 95 % confidence-level upper limits on the production cross-section times branching ratio of the $Z^\prime$ to dark quarks as a function of the $Z^\prime$ mass for various dark-quark scenarios.
Distribution of the di-jet invariant mass, $m_{\mathrm{JJ}}$ for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z'}=2.5$ TeV), shown after applying the preselections described in the text. The simulated background is normalised to the data and the signals are normalised to a production cross-section of 10 fb.
Distributions of the number of tracks associated to the leading jet, $n_{track,1}$, for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z^\prime}=2.5$ TeV), shown after applying the preselections described in the text. All distributions are normalised to unity. The uncertainty band around the background prediction corresponds to the modelling uncertainty described in Section 6.
Distributions of the number of tracks associated to the subleading jet, $n_{track,2}$, for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z^\prime}=2.5$ TeV), shown after applying the preselections described in the text. All distributions are normalised to unity. The uncertainty band around the background prediction corresponds to the modelling uncertainty described in Section 6.
A search for a heavy CP-odd Higgs boson, $A$, decaying into a $Z$ boson and a heavy CP-even Higgs boson, $H$, is presented. It uses the full LHC Run 2 dataset of $pp$ collisions at $\sqrt{s}=13$ TeV collected with the ATLAS detector, corresponding to an integrated luminosity of $140$ fb$^{-1}$. The search for $A\to ZH$ is performed in the $\ell^+\ell^- t\bar{t}$ and $\nu\bar{\nu}b\bar{b}$ final states and surpasses the reach of previous searches in different final states in the region with $m_H>350$ GeV and $m_A>800$ GeV. No significant deviation from the Standard Model expectation is found. Upper limits are placed on the production cross-section times the decay branching ratios. Limits with less model dependence are also presented as functions of the reconstructed $m(t\bar{t})$ and $m(b\bar{b})$ distributions in the $\ell^+\ell^- t\bar{t}$ and $\nu\bar{\nu}b\bar{b}$ channels, respectively. In addition, the results are interpreted in the context of two-Higgs-doublet models.
<b><u>Overview of HEPData Record</u></b><br> <b>Upper limits on cross-sections:</b> <ul> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20ggF,%20tanbeta=0.5">95% CL upper limit on ggF A->ZH(tt) production for tanb=0.5</a> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20ggF,%20tanbeta=1">95% CL upper limit on ggF A->ZH(tt) production for tanb=1</a> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20ggF,%20tanbeta=5">95% CL upper limit on ggF A->ZH(tt) production for tanb=5</a> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20bbA,%20tanbeta=1">95% CL upper limit on bbA A->ZH(tt) production for tanb=1</a> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20bbA,%20tanbeta=5">95% CL upper limit on bbA A->ZH(tt) production for tanb=5</a> <li><a href="?table=Cross-section%20limits%20for%20lltt,%20bbA,%20tanbeta=10">95% CL upper limit on bbA A->ZH(tt) production for tanb=10</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20ggA,%20tanbeta=0.5">95% CL upper limit on ggF A->ZH(bb) production for tanb=0.5</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20ggA,%20tanbeta=1">95% CL upper limit on ggF A->ZH(bb) production for tanb=1</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20ggA,%20tanbeta=5">95% CL upper limit on ggF A->ZH(bb) production for tanb=5</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20bbA,%20tanbeta=1">95% CL upper limit on bbA A->ZH(bb) production for tanb=1</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20bbA,%20tanbeta=5">95% CL upper limit on bbA A->ZH(bb) production for tanb=5</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20bbA,%20tanbeta=10">95% CL upper limit on bbA A->ZH(bb) production for tanb=10</a> <li><a href="?table=Cross-section%20limits%20for%20vvbb,%20bbA,%20tanbeta=20">95% CL upper limit on bbA A->ZH(bb) production for tanb=20</a> </ul> <b>Kinematic distributions:</b> <ul> <li><a href="?table=m(tt),L3hi_Zin,ggF-production">m(tt) distribution in the L3hi_Zin region of the lltt channel</a> <li><a href="?table=m(bb),2tag,0L,ggF-production">m(bb) distribution in the 2 b-tag 0L region of the vvbb channel</a> <li><a href="?table=m(bb),3ptag,0L,bbA-production">m(bb) distribution in the 3p b-tag 0L region of the vvbb channel</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin450,bbA-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=450 GeV hypothesis with the bbA signal shown</a> <li><a href="?table=m(tt),L3hi_Zin,bbA-production">m(tt) distribution in the L3hi_Zin region of the lltt channel with the bbA signal shown</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin350,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=350 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin400,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=400 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin450,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=450 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin500,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=500 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin550,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=550 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin600,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=600 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin700,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=700 GeV hypothesis</a> <li><a href="?table=m(lltt)-m(tt),L3hi_Zin_Hin800,ggF-production">Fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=800 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin130,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=130 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin150,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=150 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin200,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=200 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin250,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=250 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin300,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=300 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin350,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=350 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin400,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=400 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin450,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=450 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin500,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=500 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin600,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=600 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin700,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=700 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,0L_Hin800,ggF-production">Fit discriminant mT(VH) in the 2 b-tag signal region of the vvbb channel for the mH=800 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin130,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=130 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin150,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=150 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin200,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=200 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin250,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=250 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin300,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=300 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin350,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=350 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin400,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=400 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin450,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=450 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin500,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=500 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin600,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=600 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin700,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=700 GeV hypothesis</a> <li><a href="?table=mTVH,3ptag,0L_Hin800,bbA-production">Fit discriminant mT(VH) in the 3p b-tag signal region of the vvbb channel for the mH=800 GeV hypothesis</a> <li><a href="?table=mTVH,2tag,2L">Fit discriminant mT(VH) in the 2L region of the vvbb channel</a> <li><a href="?table=mTVH,2tag,em">Fit discriminant mT(VH) in the em region of the vvbb channel</a> <li><a href="?table=mTVH,3ptag,2L">Fit discriminant mT(VH) in the 2L region of the vvbb channel</a> <li><a href="?table=mTVH,3ptag,em">Fit discriminant mT(VH) in the em region of the vvbb channel</a> <li><a href="?table=lep3pt,L3hi_Zin">pT(lepton,3) distribution in the L3hi_Zin region of the lltt channel</a> <li><a href="?table=etaHrestVH,L3hi_Zin">eta(H,VH rest frame) distribution in the signal region of the lltt channel</a> <li><a href="?table=ETmiss,2tag,0L">ETmiss distribution in the 2 b-tag signal region of the vvbb channel</a> <li><a href="?table=mtopnear,2tag,0L">m(top,near) distribution in the 2 b-tag signal region of the vvbb channel</a> <li><a href="?table=ETmiss,3ptag,0L">ETmiss distribution in the 3p b-tag signal region of the vvbb channel</a> <li><a href="?table=mtopnear,3ptag,0L">m(top,near) distribution in the 3p b-tag signal region of the vvbb channel</a> </ul> <b>Observed local significance:</b> <ul> <li><a href="?table=Local%20significance,%20lltt,%20ggF%20production">ggF A->ZH->lltt signals</a> <li><a href="?table=Local%20significance,%20lltt,%20bbA%20production">bbA A->ZH->lltt signals</a> <li><a href="?table=Local%20significance,%20vvbb,%20ggF%20production">ggF A->ZH->vvbb signals</a> <li><a href="?table=Local%20significance,%20vvbb,%20bbA%20production">bbA A->ZH->vvbb signals</a> </ul> <b>Acceptance and efficiency:</b> <ul> <li><a href="?table=Acceptance*efficiency,%20lltt,%20ggF%20production">ggF A->ZH->lltt signals</a> <li><a href="?table=Acceptance*efficiency,%20lltt,%20bbA%20production">bbA A->ZH->lltt signals</a> <li><a href="?table=Acceptance*efficiency,%20vvbb,%20ggF%20production">ggF A->ZH->vvbb signals</a> <li><a href="?table=Acceptance*efficiency,%20vvbb,%20bbA%20production">bbA A->ZH->vvbb signals</a> </ul>
The distribution of the fit discriminant m(lltt)-m(tt) in the signal region of the lltt channel for the mH=450 GeV hypothesis. <br><br><a href="?table=overview">return to overview</a>
The distribution of the fit discriminant mTVH in the 2 b-tag signal region of the vvbb channel for the mH=300 GeV hypothesis. <br><br><a href="?table=overview">return to overview</a>
A search for nonresonant Higgs boson pair production in the $b\bar{b}\gamma\gamma$ final state is performed using 140 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this final state based on the same data sample. The analysis strategy is optimised to probe anomalous values not only of the Higgs ($H$) boson self-coupling modifier $\kappa_\lambda$ but also of the quartic $HHVV$ ($V=W,Z$) coupling modifier $\kappa_{2V}$. No significant excess above the expected background from Standard Model processes is observed. An observed upper limit $\mu_{HH}<4.0$ is set at 95% confidence level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The 95% confidence intervals for the coupling modifiers are $-1.4<\kappa_\lambda<6.9$ and $-0.5<\kappa_{2V}<2.7$, assuming all other Higgs boson couplings except the one under study are fixed to the Standard Model predictions. The results are interpreted in the Standard Model effective field theory and Higgs effective field theory frameworks in terms of constraints on the couplings of anomalous Higgs boson (self-)interactions.
Observed (solid line) value of $-2\ln\Lambda$ as a function of $\kappa_{\lambda}$, when all other coupling modifiers are fixed to their SM predictions.
Expected (dashed line) value of $-2\ln\Lambda$ as a function of $\kappa_{\lambda}$, when all other coupling modifiers are fixed to their SM predictions.
Observed (solid line) value of $-2\ln\Lambda$ as a function of $\kappa_{2V}$, when all other coupling modifiers are fixed to their SM predictions.
A study of the polarisation and CP properties in $ZZ$ production is presented. The used data set corresponds to an integrated luminosity of 140 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $13$ TeV recorded by the ATLAS detector at the Large Hadron Collider. The $ZZ$ candidate events are reconstructed using two same-flavour opposite-charge electron or muon pairs. The production of two longitudinally polarised $Z$ bosons is measured with a significance of 4.3 standard deviations, and its cross-section is measured in a fiducial phase space to be $2.45 \pm 0.60$ fb, consistent with the next-to-leading-order Standard Model prediction. The inclusive differential cross-section as a function of a CP-sensitive angular observable is also measured. The results are used to constrain anomalous CP-odd neutral triple gauge couplings.
Unfolded differential cross-section as a function of the Optimal Observable $\mathcal{O}_{T_{yz,1} T_{yz,3}}$
Measurements of the differential production cross-sections of prompt and non-prompt $J/\psi$ and $\psi(2$S$)$ mesons with transverse momenta between 8 and 360 GeV and rapidity in the range $|y|<2$ are reported. Furthermore, measurements of the non-prompt fractions of $J/\psi$ and $\psi(2$S$)$, and the prompt and non-prompt $\psi(2$S$)$-to-$J/\psi$ production ratios, are presented. The analysis is performed using 140 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collision data recorded by the ATLAS detector at the LHC during the years 2015-2018.
Summary of results for cross-section of prompt $J/\psi$ decaying to a muon pair for 13 TeV data in fb/GeV. Uncertainties are statistical and systematic, respectively.
Summary of results for cross-section of non-prompt $J/\psi$ decaying to a muon pair for 13 TeV data in fb/GeV. Uncertainties are statistical and systematic, respectively.
Summary of results for cross-section of prompt $\psi(2S)$ decaying to a muon pair for 13 TeV data in fb/GeV. Uncertainties are statistical and systematic, respectively.
The strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis uses a data sample corresponding to a total integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The W+c production cross section and the cross section ratio $R^\pm_\text{c}$ = $\sigma$(W$^+$+$\bar{\text{c}}$) / $\sigma$(W$^-$+$\text{c}$) are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in $R^\pm_\text{c}$. The precision of the measurements is improved with respect to previous studies, reaching 1% in $R^\pm_\text{c}$ = 0.950 $\pm$ 0.005 (stat) $\pm$ 0.010 (syst). The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics.
Particle level efficiency*acceptance correction factors and cross section measurements for the four channels (W decay to muon or electron and charm identification via muon or secondary vertex inside a jet). The combined measurement is shown in the last row.
Parton level efficiency*acceptance correction factors and cross section measurements for the four channels (W decay to muon or electron and charm identification via muon or secondary vertex inside a jet). The combined measurement is shown in the last row.
Inclusive cross section predictions at QCD NLO accuracy from MCFM using different PDF sets
A measurement of the Higgs boson (H) production via vector boson fusion (VBF) and its decay into a bottom quark-antiquark pair ($\mathrm{b\bar{b}}$) is presented using proton-proton collision data recorded by the CMS experiment at $\sqrt{s}$ = 13 TeV and corresponding to an integrated luminosity of 90.8 fb$^{-1}$. Treating the gluon-gluon fusion process as a background and constraining its rate to the value expected in the standard model (SM) within uncertainties, the signal strength of the VBF process, defined as the ratio of the observed signal rate to that predicted by the SM, is measured to be $\mu^\text{qqH}_\mathrm{Hb\bar{b}}$ = 1.01 $^{+0.55}_{-0.46}$. The VBF signal is observed with a significance of 2.4 standard deviations relative to the background prediction, while the expected significance is 2.7 standard deviations. Considering inclusive Higgs boson production and decay into bottom quarks, the signal strength is measured to be $\mu^\text{incl.}_\mathrm{Hb\bar{b}}$ = 0.99 $^{+0.48}_{-0.41}$, corresponding to an observed (expected) significance of 2.6 (2.9) standard deviations.
The mbb distribution after weighted combination of all categories in the analysis weighted with S/(S + B). where S is the total Hbb signal yield (both VBF and ggH) and B is the total background yield including QCD multijet and Z+jets
The best fit values of the signal strength modifier for the different processes. The uncertainties, corresponding to one standard deviation confidence intervals, include both statistical and systematic sources. The additional breakdown of the uncertainties into their separate statistical and systematic contributions is also shown.
The best fit values of the signal strength modifier for the different processes by floating the VBF and ggH production rates independently. The uncertainties, corresponding to one standard deviation confidence intervals, include both statistical and systematic sources. The additional breakdown of the uncertainties into their separate statistical and systematic contributions is also shown.
A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z$'$ boson couplings to a bb quark pair ($g_\mathrm{b}$), an sb quark pair ($g_\mathrm{b}\delta_\mathrm{bs}$), and any same-flavor charged lepton ($g_\ell$) or neutrino pair ($g_\nu$), with $\left|g_{\nu}\right| = \left|g_\ell\right|$. For a Z$'$ boson with a mass $m_{\mathrm{Z}'}$ = 350 GeV (2 TeV) and $\left|\delta_\mathrm{bs}\right|$$\lt$ 0.25, the majority of the parameter space with 0.0057 $\lt$$\left|g_\ell\right|$$\lt$ 0.35 (0.25 $\lt$$\left|g_\ell\right|$$\lt$ 0.43) and 0.0079 $\lt$$\left|g_\mathrm{b}\right|$$\lt$ 0.46 (0.34 $\lt$$\left|g_\mathrm{b}\right|$$\lt$ 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z$'$ model with parameters consistent with low-energy b $\to$ s$\ell\ell$ measurements. In this scenario, most of the allowed parameter space is excluded for a Z$'$ boson with 350 $\lt m_{\mathrm{Z}'}$ $\lt$ 500 GeV, while the constraints are less stringent for higher $m_{\mathrm{Z}'}$ hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date.
Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{b}\overline{\mathrm{b}}\to\mathrm{Z'}$, with one $\mathrm{b}$ quark in the final state.
Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{s}\overline{\mathrm{b}}\to\mathrm{Z'}$, with one $\mathrm{b}$ quark in the final state.
Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{b}\overline{\mathrm{b}}\to\mathrm{Z'}$, with two $\mathrm{b}$ quarks in the final state.
A search for resonances in events with the $\gamma$+jet final state has been performed using proton-proton collision data collected at $\sqrt{s}$ = 13 TeV by the CMS experiment at the LHC. The total data analyzed correspond to an integrated luminosity of 138 fb$^{-1}$. Models of excited quarks and quantum black holes are considered. Using a wide-jet reconstruction for the candidate jet, the $\gamma$+jet invariant mass spectrum measured in data is examined for the presence of resonances over the standard model continuum background. The background is estimated by fitting the mass distribution with a functional form. The data exhibit no statistically significant deviations from the expected standard model background. Exclusion limits at 95% confidence level on the resonance mass and other parameters are set. Excited light-flavor quarks (excited bottom quarks) are excluded up to a mass of 6.0 (3.8) TeV. Quantum black hole production is excluded for masses up to 7.5 (5.2) TeV in the Arkani-Hamed-Dimopoulos-Dvali (Randall-Sundrum) model. These lower mass bounds are the most stringent to date among those obtained in the $\gamma$+jet final state.
The signal cross-sections values of the signals q* with coupling mupltiplier f =1.0 and f = 0.5, as a function of resonance mass
The signal cross-sections values of the signals b* with coupling mupltiplier f =1.0 and f = 0.5, as a function of resonance mass
The signal cross-sections values of the signal QBH ADD with n=6 extra dimensions, as a function of threshold mass
Measurements of the inclusive and differential fiducial cross sections for the Higgs boson production in the H → ZZ → 4ℓ (ℓ = e, μ) decay channel are presented. The results are obtained from the analysis of proton-proton collision data recorded by the CMS experiment at the CERN LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{−1}$. The measured inclusive fiducial cross section is 2.73 ± 0.26 fb, in agreement with the standard model expectation of 2.86 ± 0.1 fb. Differential cross sections are measured as a function of several kinematic observables sensitive to the Higgs boson production and decay to four leptons. A set of double-differential measurements is also performed, yielding a comprehensive characterization of the four leptons final state. Constraints on the Higgs boson trilinear coupling and on the bottom and charm quark coupling modifiers are derived from its transverse momentum distribution. All results are consistent with theoretical predictions from the standard model.
Differential cross section measurements in bins of mass4l (v3)
Differential cross section measurements in bins of mass4l_zzfloating (v3)
Differential cross section measurements in bins of njets_pt30_eta4p7 (v3)
The mass of the top quark is measured in 36.3 fb$^{-1}$ of LHC proton-proton collision data collected with the CMS detector at $\sqrt{s}$ = 13 TeV. The measurement uses a sample of top quark pair candidate events containing one isolated electron or muon and at least four jets in the final state. For each event, the mass is reconstructed from a kinematic fit of the decay products to a top quark pair hypothesis. A profile likelihood method is applied using up to four observables to extract the top quark mass. The top quark mass is measured to be 171.77 $\pm$ 0.37 GeV. This approach significantly improves the precision over previous measurements.
Fit values for the top quark mass value and the nuisance parameters corresponding to the different uncertainty sources. All nuisance parameters have a prefit uncertainty of 1.
Covariance matrix for the top quark mass value and the nuisance parameters corresponding to the different uncertainty sources. All nuisance parameters have a prefit uncertainty of 1. The (statistical) uncertainty in mTop in the matrix includes the contributions from limited simulation sample sizes.
A search for physics beyond the standard model (SM) in the final state with a hadronically decaying tau lepton and a neutrino is presented. This analysis is based on data recorded by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, corresponding to a total integrated luminosity of 138 fb$^{=1}$. The transverse mass spectrum is analyzed for the presence of new physics. No significant deviation from the SM prediction is observed. Limits are set on the production cross section of a W' boson decaying into a tau lepton and a neutrino. Lower limits are set on the mass of the sequential SM-like heavy charged vector boson and the mass of a quantum black hole. Upper limits are placed on the couplings of a new boson to the SM fermions. Constraints are put on a nonuniversal gauge interaction model and an effective field theory model. For the first time, upper limits on the cross section of $t$-channel leptoquark (LQ) exchange are presented. These limits are translated into exclusion limits on the LQ mass and on its coupling in the $t$-channel. The sensitivity of this analysis extends into the parameter space of LQ models that attempt to explain the anomalies observed in B meson decays. The limits presented for the various interpretations are the most stringent to date. Additionally, a model-independent limit is provided.
The transverse mass distribution of $ au$ leptons and missing transverse momentum observed in the Run-2 data (black dots with statistical uncertainty) as well as the expectation from SM processes (stacked histograms). Different signal hypotheses normalized to 10 fb$^{-1}$ are illustrated as dashed lines for exemplary SSM W$\prime$ boson, QBH and EFT signal hypotheses. The ratios of the background-subtracted data yields to the expected background yields are presented in the lower panel. The combined statistical and systematic uncertainties in the background are represented by the grey shaded band in the ratio panel.
Bayesian upper exclusion limits at 95% CL on the product of the cross section and branching fraction of a W$\prime$ boson decaying to a $\tau$ lepton and a neutrino in the SSM model. For this model, W$\prime$ boson masses of up to 4.8 TeV can be excluded. The limit is given by the intersection of the observed (solid) limit and the theoretical cross section (blue dotted curve). The 68 and 95% quantiles of the limits are represented by the green and yellow bands, respectively. The $\sigma \mathcal{B}$ for an SSM W' boson, along with its associated uncertainty, calculated at NNLO precision in QCD is shown.
Bayesian 95% CL model-independent upper limit on the product of signal cross sections and branching fraction for the $\tau+\nu$ decay for a back-to-back $\tau$ lepton plus $p_{T}^{miss}$ topology. To calculate this limit, all events for signal, background, and data are summed starting from a minimum $m_{T}$ threshold and then divided by the total number of events. No assumption on signal shape is included in this limit. The expected (dashed line) and observed (solid line) limits are shown as well as the 68% and 95% CL uncertainty bands (green and yellow, respectively).
A search for long-lived particles decaying in the outer regions of the CMS silicon tracker or in the calorimeters is presented. The search is based on a data sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the CMS detector at the LHC in 2016-2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. A novel technique, using trackless and out-of-time jet information combined in a deep neural network discriminator, is employed to identify decays of long-lived particles. The results are interpreted in a simplified model of chargino-neutralino production, where the neutralino is the next-to-lightest supersymmetric particle, is long-lived, and decays to a gravitino and either a Higgs or Z boson. This search is most sensitive to neutralino proper decay lengths of approximately 0.5 m, for which masses up to 1.18 TeV are excluded at 95% confidence level. The current search is the best result to date in the mass range from the kinematic limit imposed by the Higgs mass up to 1.8 TeV.
Summary of combined statistical and systematic uncertainties, the size of their effect, and whether it applies to the signal or background yield predictions. Ranges for signal systematic uncertainties reflect their impact on different signal parameter space points.
Summary of combined statistical and systematic uncertainties, the size of their effect, and whether it applies to the signal or background yield predictions. Ranges for signal systematic uncertainties reflect their impact on different signal parameter space points.
Feynman diagrams of the effective neutralino pair production in the GMSB simplified model in which the two neutralinos decay into two gravitinos ($\tilde{G}$) and two $Z$ bosons (left), a $Z$ and a Higgs boson ($H$) (center), or two Higgs bosons (right).
A search is performed for exclusive high-mass $\gamma\gamma$$\to$ WW and $\gamma\gamma$$\to$ ZZ production in proton-proton collisions using intact forward protons reconstructed in near-beam detectors, with both weak bosons decaying into boosted and merged jets. The analysis is based on a sample of proton-proton collisions collected by the CMS and TOTEM experiments at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 100 fb$^{-1}$. No excess above the standard model background prediction is observed, and upper limits are set on the pp $\to$ pWWp and pp $\to$ pZZp cross sections in a fiducial region defined by the diboson invariant mass $m$(VV) $\lt$ 1 TeV (with V = W, Z) and proton fractional momentum loss 0.04 $\lt$$\xi$$\lt$ 0.20. The results are interpreted as new limits on dimension-6 and dimension-8 anomalous quartic gauge couplings.
Expected and observed upper limits on the AQGC operators $a^W_0/\Lambda^2$, with no unitarization. The $y$ axis shows the limit on the ratio of the observed cross section to the cross section predicted for each anomalous coupling value ($\sigma_\mathrm{AQGC}$).
Expected and observed upper limits on the AQGC operators $a^W_C/\Lambda^2$, with no unitarization. The $y$ axis shows the limit on the ratio of the observed cross section to the cross section predicted for each anomalous coupling value ($\sigma_\mathrm{AQGC}$).
Expected and observed upper limits on the AQGC operators $a^Z_0/\Lambda^2$, with no unitarization. The $y$ axis shows the limit on the ratio of the observed cross section to the cross section predicted for each anomalous coupling value ($\sigma_\mathrm{AQGC}$).
A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton+jets channel of top quark pair production ($\mathrm{t\bar{t}}$) events, where the lepton is an electron or muon. The products of the hadronic top quark decay are reconstructed using a single large-radius jet with transverse momentum greater than 400 GeV. The data were collected with the CMS detector at the LHC in proton-proton collisions and correspond to an integrated luminosity of 138 fb$^{-1}$. The differential $\mathrm{t\bar{t}}$ production cross section as a function of the jet mass is unfolded to the particle level and is used to extract the top quark mass. The jet mass scale is calibrated using the hadronic W boson decay within the large-radius jet. The uncertainties in the modelling of the final state radiation are reduced by studying angular correlations in the jet substructure. These developments lead to a significant increase in precision, and a top quark mass of 173.06 $\pm$ 0.84 GeV.
The particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section in the fiducial region as a function of the XCone-jet mass.
Correlations between bins in the particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section as a function of the XCone-jet mass.
The covariance matrix containing the statistical uncertainties of the particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section as a function of the XCone-jet mass.
The production of Z bosons associated with jets is measured in pp collisions at $\sqrt{s}$ = 13 TeV with data recorded with the CMS experiment at the LHC corresponding to an integrated luminosity of 36.3 fb$^{-1}$. The multiplicity of jets with transverse momentum $p_\mathrm{T}$$\gt$ 30 GeV is measured for different regions of the Z boson's $p_\mathrm{T}$(Z), from lower than 10 GeV to higher than 100 GeV. The azimuthal correlation $\Delta \phi$ between the Z boson and the leading jet, as well as the correlations between the two leading jets are measured in three regions of $p_\mathrm{T}$(Z). The measurements are compared with several predictions at leading and next-to-leading orders, interfaced with parton showers. Predictions based on transverse-momentum dependent parton distributions and corresponding parton showers give a good description of the measurement in the regions where multiple parton interactions and higher jet multiplicities are not important. The effects of multiple parton interactions are shown to be important to correctly describe the measured spectra in the low $p_\mathrm{T}$(Z) regions.
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $p_T<10$ GeV
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $10<p_T<30$ GeV
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $30<p_T<50$ GeV
Multijet events at large transverse momentum ($p_\mathrm{T}$) are measured at $\sqrt{s}$ = 13 TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 36.3 fb$^{-1}$. The multiplicity of jets with $p_\mathrm{T}$$>$ 50 GeV that are produced in association with a high-$p_\mathrm{T}$ dijet system is measured in various ranges of the $p_\mathrm{T}$ of the jet with the highest transverse momentum and as a function of the azimuthal angle difference $\Delta\phi_{1,2}$ between the two highest $p_\mathrm{T}$ jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest $p_\mathrm{T}$ jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $0 < \Delta\Phi_{1,2} < 150^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $150 < \Delta\Phi_{1,2} < 170^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $170 < \Delta\Phi_{1,2} < 180^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016-2018, with an integrated luminosity of 138 fb$^{-1}$. Events are separated into single-lepton, same-sign charge dilepton, and multilepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for $\mathrm{T\overline{T}}$ production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for $\mathrm{B\overline{B}}$ production with B quark decays to tW.
Distribution of ST in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.
Distribution of the leading jet’s DEEPAK8 light quark or gluon score in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.
Distribution of the MLP T quark score in the SR for the $T\overline{T}$ search. The observed data, predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario, and the background are all shown. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x10 and x20, respectively, for visibility.
The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb$^{-1}$. The inclusive fiducial cross section is measured to be $\sigma_\mathrm{fid}$ = 73.4 $_{-5.3}^{+5.4}$ (stat) ${}_{-2.2}^{+2.4}$ (syst) fb, in agreement with the standard model expectation of 75.4 $\pm$ 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed.
Differential fiducial higgs to diphoton cross section with respect to $p_{\mathrm{T}}^{\gamma\gamma}$. The last bin in the differential observable extends to infinity and the measured fiducial cross section in this bin is devided by the given bin width
Differential fiducial higgs to diphoton cross section with respect to $p_{\mathrm{T}}^{\gamma\gamma}$. The last bin in the differential observable extends to infinity and the measured fiducial cross section in this bin is devided by the given bin width
Correlation between the measured fiducial cross sections in the different bins of $p_{\mathrm{T}}^{\gamma\gamma}$
Three searches are presented for signatures of physics beyond the standard model (SM) in $\tau\tau$ final states in proton-proton collisions at the LHC, using a data sample collected with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into $\tau$ leptons and the cross sections for the production of a new boson $\phi$, in addition to the H(125) boson, via gluon fusion (gg$\phi$) or in association with b quarks, ranging from $\mathcal{O}$(10 pb) for a mass of 60 GeV to 0.3 fb for a mass of 3.5 TeV each. The data reveal two excesses for gg$\phi$ production with local $p$-values equivalent to about three standard deviations at $m_\phi$ = 0.1 and 1.2 TeV. In a search for $t$-channel exchange of a vector leptoquark U$_1$, 95% CL upper limits are set on the dimensionless U$_1$ leptoquark coupling to quarks and $\tau$ leptons ranging from 1 for a mass of 1 TeV to 6 for a mass of 5 TeV, depending on the scenario. In the interpretations of the $M_\mathrm{h}^{125}$ and $M_\mathrm{h, EFT}^{125}$ minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below 350 GeV are excluded at 95% CL.
Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $gg\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $bb\phi$ production rate has been profiled. The peak in the expected $gg\phi$ limit is tribute to a loss of sensitivity around $90\text{ GeV}$ due to the background from $Z/\gamma^\ast\rightarrow\tau\tau$ events. Numerical values provided in this table correspond to Figure 10a of the publication.
Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $bb\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $gg\phi$ production rate has been profiled. Numerical values provided in this table correspond to Figure 10b of the publication.
Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $gg\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $bb\phi$ production rate has been fixed to zero. Numerical values provided in this table correspond to Figure 37 of the auxilliary material of the publication.
A measurement of the top quark pole mass $m_\mathrm{t}^\text{pole}$ in events where a top quark-antiquark pair ($\mathrm{t\bar{t}}$) is produced in association with at least one additional jet ($\mathrm{t\bar{t}}$+jet) is presented. This analysis is performed using proton-proton collision data at $\sqrt{s}$ = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb$^{-1}$. Events with two opposite-sign leptons in the final state (e$^+$e$^-$, $\mu^+\mu^-$, e$^\pm\mu^\mp$) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the $\mathrm{t\bar{t}}$+jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in $m_\mathrm{t}^\text{pole}$ = 172.93 $\pm$ 1.36 GeV.
Absolute differential cross section as a function of the rho observable at parton level.
Covariance matrix for the total uncertainty (i.e. fit including stat., not extrapolation) for the measurement of the absolute differential cross section as a function of the rho observable at parton level.
Covariance matrix for the statistical uncertainty for the measurement of the absolute differential cross section as a function of the rho observable at parton level.
A search for a charged Higgs boson H$^\pm$ decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016-2018 at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H$^\pm$ in the mass range of 300-700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H$^\pm$ mass of 300 GeV to 0.019 pb for a mass of 700 GeV. These are the first limits on H$^\pm$ production in the H$^\pm$ $\to$ HW$^\pm$ decay channel at the LHC.
Expected and observed upper limits at 95% CL on the product of cross section and branching fraction as a function of mH+ and assuming mH = 200 GeV for the combination of all final states considered.
The results of a search for Higgs boson pair (HH) production in the WW*WW*, WW*$\tau\tau$, and $\tau\tau\tau\tau$ decay modes are presented. The search uses 138 fb$^{-1}$ of proton-proton collision data recorded by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV from 2016 to 2018. Analyzed events contain two, three, or four reconstructed leptons, including electrons, muons, and hadronically decaying tau leptons. No evidence for a signal is found in the data. Upper limits are set on the cross section for nonresonant HH production, as well as resonant production in which a new heavy particle decays to a pair of Higgs bosons. For nonresonant production, the observed (expected) upper limit on the cross section at 95% confidence level (CL) is 21.3 (19.4) times the standard model (SM) prediction. The observed (expected) ratio of the trilinear Higgs boson self-coupling to its value in the SM is constrained to be within the interval $-$6.9 to 11.1 ($-$6.9 to 11.7) at 95% CL, and limits are set on a variety of new-physics models using an effective field theory approach. The observed (expected) limits on the cross section for resonant HH production range from 0.18 to 0.90 (0.08 to 1.06) pb at 95% CL for new heavy-particle masses in the range 250-1000 GeV.
Distribution of an input to the BDT classifier in the $2\ell$(ss) category: The scalar $p_{T}$ sum, denoted as $H_{T}$, of the two reconstructed $\ell$ and all small-radius jets.
Distribution of an input to the BDT classifier in the $2\ell$(ss) category: The angular separation $\Delta R$ between the two $\ell$.
Distribution of an input to the BDT classifier in the $3\ell$ category: The angular separation between $\ell_{3}$ and the nearest small-radius jet (j). The $\ell_{3}$ in is defined as the $\ell$ that is not part of the opposite-sign $\ell\ell$ pair of lowest mass.
A search for pairs of dijet resonances with the same mass is conducted in final states with at least four jets. Results are presented separately for the case where the four jet production proceeds via an intermediate resonant state and for nonresonant production. The search uses a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ collected by the CMS detector in proton-proton collisions at $\sqrt{s}$ = 13 TeV. Model-independent limits, at 95% confidence level, are reported on the production cross section of four-jet and dijet resonances. These first LHC limits on resonant pair production of dijet resonances via high mass intermediate states are applied to a signal model of diquarks that decay into pairs of vector-like quarks, excluding diquark masses below 7.6 TeV for a particular model scenario. There are two events in the tails of the distributions, each with a four-jet mass of 8 TeV and an average dijet mass of 2 TeV, resulting in local and global significances of 3.9 and 1.6 standard deviations, respectively, if interpreted as a signal. The nonresonant search excludes pair production of top squarks with masses between 0.50 TeV to 0.77 TeV, with the exception of a small interval between 0.52 and 0.58 TeV, for supersymmetric $R$-parity-violating decays to quark pairs, significantly extending previous limits. Here, the most significant excess above the predicted background occurs at an average dijet mass of 0.95 TeV, for which the local and global significances are 3.6 and 2.5 standard deviations, respectively.
The observed 95% CL upper limits on the product of the cross section, branching fraction, and acceptance for resonant production of paired dijet resonances decaying to a quark-gluon pair, with $M(X)/M(Y) = 0.11$. The corresponding expected limits and their variations at the 1 and 2 standard deviation levels are also shown. Limits are compared to predictions for a scalar diquark with couplings to pairs of up quarks, $y_{uu}$ = 0.4, and to pairs of vector-like quarks, $y_{χ}$ = 0.6.
The observed 95% CL upper limits on the product of the cross section, branching fraction, and acceptance for resonant production of paired dijet resonances decaying to a quark-gluon pair, with $M(X)/M(Y) = 0.13$. The corresponding expected limits and their variations at the 1 and 2 standard deviation levels are also shown. Limits are compared to predictions for a scalar diquark with couplings to pairs of up quarks, $y_{uu}$ = 0.4, and to pairs of vector-like quarks, $y_{χ}$ = 0.6.
The observed 95% CL upper limits on the product of the cross section, branching fraction, and acceptance for resonant production of paired dijet resonances decaying to a quark-gluon pair, with $M(X)/M(Y) = 0.15$. The corresponding expected limits and their variations at the 1 and 2 standard deviation levels are also shown. Limits are compared to predictions for a scalar diquark with couplings to pairs of up quarks, $y_{uu}$ = 0.4, and to pairs of vector-like quarks, $y_{χ}$ = 0.6.
An inclusive search for long-lived exotic particles decaying to a pair of muons is presented. The search uses data collected by the CMS experiment at the CERN LHC in proton-proton collisions at $\sqrt{s}$ = 13 TeV in 2016 and 2018 and corresponding to an integrated luminosity of 97.6 fb$^{-1}$. The experimental signature is a pair of oppositely charged muons originating from a common secondary vertex spatially separated from the pp interaction point by distances ranging from several hundred $\mu$m to several meters. The results are interpreted in the frameworks of the hidden Abelian Higgs model, in which the Higgs boson decays to a pair of long-lived dark photons Z$_\mathrm{D}$, and of a simplified model, in which long-lived particles are produced in decays of an exotic heavy neutral scalar boson. For the hidden Abelian Higgs model with $m_\mathrm{Z_D}$ greater than 20 GeV and less than half the mass of the Higgs boson, they provide the best limits to date on the branching fraction of the Higgs boson to dark photons for $c\tau$(Z$_\mathrm{D}$) (varying with $m_\mathrm{Z_D}$) between 0.03 and ${\approx}$ 0.5 mm, and above ${\approx}$ 0.5 m. Our results also yield the best constraints on long-lived particles with masses larger than 10 GeV produced in decays of an exotic scalar boson heavier than the Higgs boson and decaying to a pair of muons.
Level-1 muon trigger efficiency in cosmic-ray muon data (blue) and signal simulation (red) as a function of $d_0$, for the Level-1 trigger $p_T$ threshold used in the 2016 analysis triggers. The denominator in the efficiency calculation is the number of STA muons with $|\eta| < 1.2$ and $p_T > 33$ GeV.
Level-1 muon trigger efficiency in cosmic-ray muon data (blue) and signal simulation (red) as a function of $d_0$, for the Level-1 trigger $p_T$ threshold used in the 2016 analysis triggers. The denominator in the efficiency calculation is the number of STA muons with $|\eta| < 1.2$ and $p_T > 33$ GeV.
Level-1 muon trigger efficiency in cosmic-ray muon data (blue) and signal simulation (red) as a function of $d_0$, for the Level-1 trigger $p_T$ threshold used in the 2018 analysis triggers. The denominator in the efficiency calculation is the number of STA muons with $|\eta| < 1.2$ and $p_T > 28$ GeV.
Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb$^{-1}$. The search uses two observables, $\mathcal{O}_1$ and $\mathcal{O}_3$, which are Lorentz scalars. The observable $\mathcal{O}_1$ is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while $\mathcal{O}_3$ consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model.
Measured asymmetries of O_1 and O_3 with statistical uncertainties
The measured asymmetries of O_1 and O_3, and dimensionless CEDM \ImdtG, extracted using the asymmetries in O_1 and O_3, with their uncertainties.
Results for the covariance matrix where the parameters a and b are taken from a linear fit (equation 11) to the different CP-violating samples (CEMD).
A search is reported for heavy resonances and quantum black holes decaying into e$\mu$, e$\tau$, and $\mu\tau$ final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016-2018 at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The e$\mu$, e$\tau$, and $\mu\tau$ invariant mass spectra are reconstructed, and no evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on the product of the cross section and branching fraction for lepton flavor violating signals. Three benchmark signals are studied: resonant $\tau$ sneutrino production in $R$ parity violating supersymmetric models, heavy Z' gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant $\tau$ sneutrinos are excluded for masses up to 4.2 TeV in the e$\mu$ channel, 3.7 TeV in the e$\tau$ channel, and 3.6 TeV in the $\mu\tau$ channel. A Z' boson with lepton flavor violating couplings is excluded up to a mass of 5.0 TeV in the e$\mu$ channel, up to 4.3 TeV in the e$\tau$ channel, and up to 4.1 TeV in the $\mu\tau$ channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6 TeV in the e$\mu$ channel, 5.2 TeV in the e$\tau$ channel, and 5.0 TeV in the $\mu\tau$ channel. In addition, model-independent limits are extracted to allow comparisons with other models for the same final states and similar event selection requirements. The results of these searches provide the most stringent limits available from collider experiments for heavy particles that undergo lepton flavor violating decays.
Mass distributions for the e$\mu$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
Mass distributions for the e$\tau$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
Mass distributions for the $\mu\tau$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
The double differential cross sections of the Drell-Yan lepton pair ($\ell^+\ell^-$, dielectron or dimuon) production are measured as functions of the invariant mass $m_{\ell\ell}$, transverse momentum $p_\mathrm{T}(\ell\ell)$, and $\phi^*_\eta$. The $\phi^*_\eta$ observable, derived from angular measurements of the leptons and highly correlated with $p_\mathrm{T}(\ell\ell)$, is used to probe the low-$p_\mathrm{T}(\ell\ell)$ region in a complementary way. Dilepton masses up to 1 TeV are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation of the systematic uncertainty, the ratios of the differential cross sections for various $m_{\ell\ell}$ ranges to those in the Z mass peak interval are presented. The collected data correspond to an integrated luminosity of 36.3 fb$^{-1}$ of proton-proton collisions recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV. Measurements are compared with predictions based on perturbative quantum chromodynamics, including soft-gluon resummation.
The measured differential cross section in the $50 \le M_{ll} < 76$ GeV mass window, in bins of the dilepton transverse momentum. The values are normalized by the bin width.
The measured differential cross section in the $50 \le M_{ll} < 76$ GeV mass window, in bins of the dilepton transverse momentum. The values are normalized by the bin width. This entry contains the covariance matrix of the results.
The measured differential cross section in the $76 \le M_{ll} < 106$ GeV mass window, in bins of the dilepton transverse momentum. The values are normalized by the bin width.
Results are presented on a search for CP violation in the production and decay of top quark-antiquark pairs in the lepton+jets channel. The search is based on data from proton-proton collisions at 13 TeV, collected with the CMS detector, corresponding to an integrated luminosity of 138 fb$^{-1}$. Possible CP violation effects are evaluated by measuring uncorrected asymmetries in observables constructed from linearly independent four-momentum vectors of the final-state particles. The dimensionless chromoelectric dipole moment of the top quark obtained from the observed asymmetries is measured to be 0.04 $\pm$ 0.10 (stat) $\pm$ 0.07 (syst), and the asymmetries exhibit no evidence for CP-violating effects, consistent with expectations from the standard model.
Results for the measurement of the effective asymmetries for each observable for the separate electron and muon channels, as well as for the combined lepton+jets channel.
Results for the measurement of the dimensionless CEDM for each observable and the combined lepton+jets channel.
Results for the measurement of the CP-violating asymmetries for each observable for the combined lepton+jets channel.
A search is reported for pairs of light Higgs bosons (H$_1$) produced in supersymmetric cascade decays in final states with small missing transverse momentum. A data set of LHC pp collisions collected with the CMS detector at $\sqrt{s}$ = 13 TeV and corresponding to an integrated luminosity of 138 fb$^{-1}$ is used. The search targets events where both H$_1$ bosons decay into $\mathrm{b\bar{b}}$ pairs that are reconstructed as large-radius jets using substructure techniques. No evidence is found for an excess of events beyond the background expectations of the standard model (SM). Results from the search are interpreted in the next-to-minimal supersymmetric extension of the SM, where a "singlino" of small mass leads to squark and gluino cascade decays that can predominantly end in a highly Lorentz-boosted singlet-like H$_1$ and a singlino-like neutralino of small transverse momentum. Upper limits are set on the product of the squark or gluino pair production cross section and the square of the $\mathrm{b\bar{b}}$ branching fraction of the H$_1$ in a benchmark model containing almost mass-degenerate gluinos and light-flavour squarks. Under the assumption of an SM-like H$_1$$\to$$\mathrm{b\bar{b}}$ branching fraction, H$_1$ bosons with masses in the range 40-120 GeV arising from the decays of squarks or gluinos with a mass of 1200 to 2500 GeV are excluded at 95% confidence level.
Reference acceptance times efficiency values for the kinematic selection and $H_T>3500\;\mathrm{GeV}$ requirements ($A_{\mathrm{kin}}$) for the benchmark signal model with different values of $m_{\mathrm{SUSY}}$. These values are independent of $m_{\mathrm{H_1}}$ within 2% in the range $30 \le m_{\mathrm{H_1}} \le 125\;\mathrm{GeV}$.
Upper limits at 95% CL on $\sigma\times\mathcal{B}^2(\mathrm{H}_1\rightarrow b\bar{b}) \times A_{\mathrm{kin}}$ as a function of $m_{\mathrm{H_1}}$. The results are independent of $m_{\mathrm{SUSY}}$ within 10% in the range $1600<m_{\mathrm{SUSY}}<2800\;\mathrm{GeV}$.
Upper limits at 95% CL on $\sigma\times\mathcal{B}^2(\mathrm{H}_1\rightarrow b\bar{b})$ as a function of $m_{\mathrm{H_1}}$ for $m_{\mathrm{SUSY}}=1200\;\mathrm{GeV}$.
Results are presented from a search for the Higgs boson decay H $\to$ Z$\gamma$, where Z $\to$$\ell^+\ell^-$ with $\ell$ = e or $\mu$. The search is performed using a sample of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. Events are assigned to mutually exclusive categories, which exploit differences in both event topology and kinematics of distinct Higgs production mechanisms to enhance signal sensitivity. The signal strength $\mu$, defined as the product of the cross section and the branching fraction [$\sigma($pp $\to$ H$)\mathcal{B}($H $\to$ Z$\gamma)$] relative to the standard model prediction, is extracted from a simultaneous fit to the $\ell^+\ell^-\gamma$ invariant mass distributions in all categories and is found to be $\mu$ = 2.4 $\pm$ 0.9 for a Higgs boson mass of 125.38 GeV. The statistical significance of the observed excess of events is 2.7 standard deviations. This measurement corresponds to $\sigma($pp $\to$ H$)\mathcal{B}($H $\to$ Z$\gamma)$ = 0.21 $\pm$ 0.08 pb. The observed (expected) upper limit at 95% confidence level on $\mu$ is 4.1 (1.8). The ratio of branching fractions $\mathcal{B}($H $\to$ Z$\gamma) / \mathcal{B}($H $\to$ $\gamma\gamma)$ is measured to be 1.5 $^{+0.7}_{-0.6}$, which agrees with the standard model prediction of 0.69 $\pm$ 0.04 at the 1.5 standard deviation level.
The $\mathcal{D}_{\mathrm{VBF}}$ distributions for signal, simulated background, and data. The $\mathcal{D}_{\mathrm{VBF}}$ distribution includes only dijet-tagged events. The sum of contributions from all signal production mechanisms is shown by the blue line, while the contribution from only the VBF mechanism is shown by the red line. The uncertainty band incorporates all statistical and systematic uncertainties in the expected background. The dashed lines indicate the boundaries for dijet-tagged categories.
The $\mathcal{D}_{\mathrm{kin}}$ distributions for signal, simulated background, and data. The $\mathcal{D}_{\mathrm{kin}}$ distribution includes only untagged events. The sum of contributions from all signal production mechanisms is shown by the blue line. The uncertainty band incorporates all statistical and systematic uncertainties in the expected background. The dashed lines indicate the boundaries for untagged categories. The gray shaded region in the $\mathcal{D}_{\mathrm{kin}}$ distribution is excluded from the analysis.
Fits to the $m_{\ell^+\ell^-\gamma}$ data distribution in the lepton-tagged categories. In the upper panel, the red solid line shows the result of a signal-plus-background fit to the given category. The red dashed line shows the background component of the fit. The green and yellow bands represent the 68 and 95% CL uncertainties in the fit. Also plotted is the expected SM signal, scaled by a factor of 10. In the lower panel, the data minus the background component of the fit is shown.
A search is presented for a heavy W' boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using proton-proton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are selected using jet substructure techniques to reduce standard model backgrounds, resulting in a distinct three-jet W' boson decay signature. No significant deviation in data with respect to the standard model background prediction is observed. Upper limits are set at 95% confidence level on the product of the W' boson cross section and the final state branching fraction. A W' boson with a mass below 3.1 TeV is excluded, given the benchmark model assumption of democratic branching fractions. In addition, limits are set based on generalizations of these assumptions. These are the most sensitive limits to date for this final state.
Reconstructed W′ boson mass distributions in the tHb signal region.
Reconstructed W′ boson mass distributions in the tZb signal region.
The W' boson 95% CL limits on the product of cross section and branching fraction. The expected and observed limits are shown for the center VLQ mass range.
Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width - related to its lifetime - is an important parameter. One way to determine this quantity is by measuring its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here, we report evidence for such off-shell contributions to the production cross section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at 95% confidence level. The scenario with no off-shell contribution is excluded at a $p$-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as $\Gamma_{\mathrm{H}}$ = 3.2 $_{-1.7}^{+2.4}$ MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs.
GGsm vs -2dNLL (SM-like (f_{ai}=0) observed)
GGsm vs -2dNLL (f_{a2} (u) observed)
GGsm vs -2dNLL (f_{a3} (u) observed)
Results are presented from a search for charged-lepton flavor violating (CLFV) interactions in top quark production and decay in pp collisions at a center-of-mass energy of 13 TeV. The events are required to contain one oppositely charged electron-muon pair in the final state, along with at least one jet identified as originating from a bottom quark. The data correspond to an integrated luminosity of 138 fb$^{-1}$, collected by the CMS experiment at the LHC. This analysis includes both the production (q $\to$ e$\mu$t) and decay (t $\to$ e$\mu$q) modes of the top quark through CLFV interactions, with q referring to a u or c quark. These interactions are parametrized using an effective field theory approach. With no significant excess over the standard model expectation, the results are interpreted in terms of vector-, scalar-, and tensor-like CLFV four-fermion effective interactions. Finally, observed exclusion limits are set at 95% confidence levels on the respective branching fractions of a top quark to an e$\mu$ pair and an up (charm) quark of 0.13 $\times$ 10$^{-6}$ (1.31 $\times$ 10$^{-6}$), 0.07 $\times$ 10$^{-6}$ (0.89 $\times$ 10$^{-6}$), and 0.25 $\times$ 10$^{-6}$ (2.59 $\times$ 10$^{-6}$) for vector, scalar, and tensor CLFV interactions, respectively.
The expected and observed upper limits on the signal cross sections.
The expected and observed upper limits on CLFV Wilson coefficients. The Limits on the Wilson coefficients are extracted from the upper limits on the cross sections. Since the cross sections are quadratic functions of the Wilson coefficients, the limits lie on an ellipse given by the coordinate intersections.
The expected and observed upper limits on top quark CLFV branching fractions. The Limits on the top quark CLFV branching fractions are extracted from the upper limits on the Wilson coefficients.
The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions in the decay channel with two oppositely charged leptons (e$^\pm\mu^\mp$, e$^+$e$^-$, or $\mu^+\mu^-$). The measurement is performed using 138 fb$^{-1}$ of proton-proton collision data recorded by the CMS experiment at $\sqrt{s} =$ 13 TeV during the 2016-2018 data-taking period of the CERN LHC. A fiducial phase space is defined such that photons radiated by initial-state particles, top quarks, or any of their decay products are included. An inclusive cross section of 175.2 $\pm$ 2.5 (stat) $\pm$ 6.3 (syst) fb is measured in a signal region with at least one jet coming from the hadronization of a bottom quark and exactly one photon with transverse momentum above 20 GeV. Differential cross sections are measured as functions of several kinematic observables of the photon, leptons, and jets, and compared to standard model predictions. The measurements are also interpreted in the standard model effective field theory framework, and limits are found on the relevant Wilson coefficients from these results alone and in combination with a previous CMS measurement of the $\mathrm{t\bar{t}}\gamma$ production process using the lepton+jets final state.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $e\mu$ channel, after the fit to the data.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $ee$ channel, after the fit to the data.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $\mu\mu$ channel, after the fit to the data.
A search for heavy neutral leptons (HNLs), the right-handed Dirac or Majorana neutrinos, is performed in final states with three charged leptons (electrons or muons) using proton-proton collision data collected by the CMS experiment at $\sqrt{s} =$ 13 TeV at the CERN LHC. The data correspond to an integrated luminosity of 138 fb$^{-1}$. The HNLs could be produced through mixing with standard model neutrinos $\nu$. For small values of the HNL mass ($\lt$ 20 GeV) and the square of the HNL-$\nu$ mixing parameter (10$^{-7}$-10$^{-2}$), the decay length of these particles can be large enough so that the secondary vertex of the HNL decay can be resolved with the CMS silicon tracker. The selected final state consists of one lepton emerging from the primary proton-proton collision vertex, and two leptons forming a displaced, secondary vertex. No significant deviations from the standard model expectations are observed, and constraints are obtained on the HNL mass and coupling strength parameters, excluding previously unexplored regions of parameter space in the mass range 1-20 GeV and squared mixing parameter values as low as 10$^{-7}$.
Number of predicted and observed events in the $eeX$ final states. The quoted uncertainties include statistical and systematic uncertainties.
Number of predicted and observed events in the $\mu\mu X$ final states. The quoted uncertainties include statistical and systematic uncertainties.
Number of predicted signal events in the $eeX$ final states, for several benchmark signal hypotheses for Majorana HNL. The quoted uncertainties include statistical and systematic uncertainties.
Results are presented from a search for physics beyond the standard model in proton-proton collisions at $\sqrt{s} =$ 13 TeV in channels with two Higgs bosons, each decaying via the process H $\to$$\mathrm{b\bar{b}}$, and large missing transverse momentum. The search uses a data sample corresponding to an integrated luminosity of 137 fb$^{-1}$ collected by the CMS experiment at the CERN LHC. The search is motivated by models of supersymmetry that predict the production of neutralinos, the neutral partners of the electroweak gauge and Higgs bosons. The observed event yields in the signal regions are found to be consistent with the standard model background expectations. The results are interpreted using simplified models of supersymmetry. For the electroweak production of nearly mass-degenerate higgsinos, each of whose decay chains yields a neutralino ($\tilde{\chi}^0_1$) that in turn decays to a massless goldstino and a Higgs boson, $\tilde{\chi}^0_1$ masses in the range 175 to 1025 GeV are excluded at 95% confidence level. For the strong production of gluino pairs decaying via a slightly lighter $\tilde{\chi}^0_2$ to H and a light $\tilde{\chi}^0_1$, gluino masses below 2330 GeV are excluded.
Predicted background and observed yields vs bin index
Cross section 95% CL upper limit vs m($\widetilde{\chi}^0_1$) for SMS model TChiHH-G.
Theory cross sections vs m($\widetilde{\chi}^0_1$) for SMS model TChiHH-G.
A search is presented for single production of a vector-like T quark with charge 2/3 $e$, in the decay channel featuring a top quark and a Z boson, with the top quark decaying hadronically and the Z boson decaying to neutrinos. The search uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$ recorded at the CERN LHC in 2016-2018. The search is sensitive to a T quark mass between 0.6 and 1.8 TeV with decay widths ranging from negligibly small up to 30% of the T quark mass. Reconstruction strategies for the top quark are based on the degree of Lorentz boosting of its final state. At 95% confidence level, the upper limit on the product of the cross section and branching fraction for a T quark of small decay width varies between 15 and 602 fb, depending on its mass. For a T quark with decay widths between 10 and 30% of its mass, this upper limit ranges between 16 and 836 fb. For most of the studied range, the results provide the best limits to date. This is the first search for single T quark production based on the full Run 2 data set of the LHC.
Product of efficiency and acceptance of the event selection for T signal events as a function of the particle mass $m_\mathrm{T}$ and width $\Gamma$ for the different hypotheses considered.
Product of efficiency and acceptance of the event selection for T signal events as a function of the particle mass $m_\mathrm{T}$ and width $\Gamma$ for the different hypotheses considered.
Product of efficiency and acceptance of the event selection for T signal events as a function of the particle mass $m_\mathrm{T}$ and width $\Gamma$ for the different hypotheses considered.
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