Search for new physics in high-mass diphoton events from proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-EXO-22-024, 2024.
Inspire Record 2787227 DOI 10.17182/hepdata.150677

Results are presented from a search for new physics in high-mass diphoton events from proton-proton collisions at $\sqrt{s}$ = 13 TeV. The data set was collected in 2016-2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb$^{-1}$. Events with a diphoton invariant mass greater than 500\GeV are considered. Two different techniques are used to predict the standard model backgrounds: parametric fits to the smoothly-falling background and a first-principles calculation of the standard model diphoton spectrum at next-to-next-to-leading order in perturbative quantum chromodynamics calculations. The first technique is sensitive to resonant excesses while the second technique can identify broad differences in the invariant mass shape. The data are used to constrain the production of heavy Higgs bosons, Randall-Sundrum gravitons, the large extra dimensions model of Arkani-Hamed, Dimopoulos, and Dvali (ADD), and the continuum clockwork mechanism. No statistically significant excess is observed. The present results are the strongest limits to date on ADD extra dimensions and RS gravitons with a coupling parameter greater than 0.1.

16 data tables

The product of the event selection efficiency (e) and the detector acceptance (A) is shown as a function of the signal resonance mass mX for the narrow signal width hypothesis ($\Gamma_{X}/m_{X} = 1.4 x 10^{4}$ for J = 0 and $~k = 0.01$ for J = 2). The total (black), EBEB (red), and EBEE (blue) curves are shown for spin (J) hypotheses J = 0 (solid) and J = 2 (dashed).

Figure 2: Observed diphoton invariant mass spectra for the EBEB category for the full Run 2 data set are shown. Also shown are the results of a likelihood fit to the background-only hypothesis. The black, red, green and blue lines indicate the result of the fit functions f1, f2, f3, and f4, respectively. The lower panels show the difference between the data and f1 fit, divided by the statistical uncertainty in the data points. dijet f1 = 0.13116092* pow(x,5.7466302555276645-0.7807885712668643*log(x)), expow1 f2 = 7.3165496e+10*exp(-0.0016273075*x)*pow(x, -1*1.8233539*1.8233539), invpow1 f3 = 8760.6423*(pow(1+x*0.0022831415,-1.*2.7013689*2.7013689)), invpowlin1 f4 = 2124447.3*(pow(1+0.029456453*x,-3.8645171-0.00027603566*x)).

Figure 2: Observed diphoton invariant mass spectra for the EBEE category for the full Run 2 data set are shown. Also shown are the results of a likelihood fit to the background-only hypothesis. The black, red, green and blue lines indicate the result of the fit functions f1, f2, f3, and f4, respectively. The lower panels show the difference between the data and f1 fit, divided by the statistical uncertainty in the data points. dijet f1 = 1.81866e-22*pow(x,19.5547-1.7634*log(x)), expow1 f2 = 69750*exp(-0.00368224*x)*pow(x, -1.*0.975269*0.975269, invpow1 f3 = 508.838*pow(1+x*0.000294278,-1.*4.5514*4.5514), invpowlin1 f4 = 470.588*pow(1+x* 5.07338e-05,-114.601+0.00817169*x)

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Search for pair production of boosted Higgs bosons via vector-boson fusion in the $b\bar{b}b\bar{b}$ final state using $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2024-092, 2024.
Inspire Record 2781483 DOI 10.17182/hepdata.150977

A search for Higgs boson pair production via vector-boson fusion is performed in the Lorentz-boosted regime, where a Higgs boson candidate is reconstructed as a single large-radius jet, using 140 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} = 13$ TeV recorded by the ATLAS detector at the Large Hadron Collider. Only Higgs boson decays into bottom quark pairs are considered. The search is particularly sensitive to the quartic coupling between two vector bosons and two Higgs bosons relative to its Standard Model prediction, $\kappa_{2V}$. This study constrains $\kappa_{2V}$ to $0.55 < \kappa_{2V} < 1.49$ at 95% confidence level. The value $\kappa_{2V} = 0$ is excluded with a significance of 3.8 standard deviations with other Higgs boson couplings fixed to their Standard Model values. A search for new heavy spin-0 resonances that would mediate Higgs boson pair production via vector-boson fusion is carried out in the mass range of 1-5 TeV for the first time under several model and decay-width assumptions. No significant deviation from the Standard Model hypothesis is observed and exclusion limits at 95% confidence level are derived.

23 data tables

The mass planes of the reconstructed Higgs boson candidates for the 1Pass selections of the analysis, shown for the data events.

The mass planes of the reconstructed Higgs boson candidates for the 2Pass selections of the analysis, shown for the data events.

The mass planes of the reconstructed Higgs boson candidates for the 2Pass selections of the analysis, shown for the VBF SM $\kappa_{2V} = 1$ HH samples.

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Searches for Higgs Boson Production through Decays of Heavy Resonances

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-B2G-23-002, 2024.
Inspire Record 2771692 DOI 10.17182/hepdata.146897

The discovery of the Higgs boson has led to new possible signatures for heavy resonance searches at the LHC. Since then, search channels including at least one Higgs boson plus another particle have formed an important part of the program of new physics searches. In this report, the status of these searches by the CMS Collaboration is reviewed. Searches are discussed for resonances decaying to two Higgs bosons, a Higgs and a vector boson, or a Higgs boson and another new resonance, with proton-proton collision data collected at $\sqrt{s}$ = 13 TeV in the years 2016-2018. A combination of the results of these searches is presented together with constraints on different beyond-the-standard model scenarios, including scenarios with extended Higgs sectors, heavy vector bosons and extra dimensions. Studies are shown for the first time by CMS on the validity of the narrow-width approximation in searches for the resonant production of a pair of Higgs bosons. The potential for a discovery at the High Luminosity LHC is also discussed.

6 data tables

Upper limits on σB for a spin-0 resonance X obtained from the combination of the individual channels. The 68 and 95% CL intervals on the expected upper limits are shown as colored bands.

Upper limits on σB for a spin-2 resonance G obtained from the combination of the individual channels. The 68 and 95% CL intervals on the expected upper limits are shown as colored bands.

Upper limits at 95% CL on $\sigma$B(pp→X→Y(bb)H) for combination as a function of m$_Y$.

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Observation of the J/$\psi$$\to$$\mu^+\mu^-\mu^+\mu^-$ decay in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-BPH-22-006, 2024.
Inspire Record 2769595 DOI 10.17182/hepdata.147273

The J/$\psi$$\to$$\mu^+\mu^-\mu^+\mu^-$ decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 33.6 fb${-1}$. Normalizing to the J/$\psi$$\to$$\mu^+\mu^-$ decay mode leads to a branching fraction [10.1$^{+3.3}_{-2.7}$ (stat) $\pm$ 0.4 (syst) ]$\times$ 10$^{-7}$, a value that is consistent with the standard model prediction.

2 data tables

$\mathrm{J}\mspace{-2mu}/\mspace{-2mu}\psi \to \mu\mu\mu\mu$ branching fraction

$\mathcal{B}(\mathrm{J}\mspace{-2mu}/\mspace{-2mu}\psi \to \mu\mu\mu\mu)$ / $\mathcal{B}(\mathrm{J}\mspace{-2mu}/\mspace{-2mu}\psi \to \mu\mu)$ ratio


Search for long-lived heavy neutrinos in the decays of B mesons produced in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-EXO-22-019, 2024.
Inspire Record 2766369 DOI 10.17182/hepdata.147308

A search for long-lived heavy neutrinos (N) in the decays of \PB mesons produced in proton-proton collisions at $\sqrt{s}$ = 13 TeV is presented. The data sample corresponds to an integrated luminosity of 41.6 fb$^{-1}$ collected in 2018 by the CMS experiment at the CERN LHC, using a dedicated data stream that enhances the number of recorded events containing B mesons. The search probes heavy neutrinos with masses in the range 1 $\lt$$m_\mathrm{N}$$\lt$ 3 GeV and decay lengths in the range 10$^{-2}$$\lt$$c\tau$$\lt$ 10$^{4}$ mm, where $\tau_\mathrm{N}$ is the N proper mean lifetime. Signal events are defined by the signature B $\to$$\ell_\mathrm{B}$NX; N $\to$$\ell^{\pm} \pi^{\mp}$, where the leptons $\ell_\mathrm{B}$ and $\ell$ can be either a muon or an electron, provided that at least one of them is a muon. The hadronic recoil system, X, is treated inclusively and is not reconstructed. No significant excess of events over the standard model background is observed in any of the $\ell^{\pm}\pi^{\mp}$ invariant mass distributions. Limits at 95% confidence level on the sum of the squares of the mixing amplitudes between heavy and light neutrinos, $\vert V_\mathrm{N}\vert^2$, and on $c\tau$ are obtained in different mixing scenarios for both Majorana and Dirac-like N particles. The most stringent upper limit $\vert V_\mathrm{N}\vert^2$ $\lt$ 2.0$\times$10$^{-5}$ is obtained at $m_\mathrm{N}$ = 1.95 GeV for the Majorana case where N mixes exclusively with muon neutrinos. The limits on $\vert V_\mathrm{N}\vert^2$ for masses 1 $\lt$ $m_\mathrm{N}$ $\lt$ 1.7 GeV are the most stringent from a collider experiment to date.

14 data tables

Expected and observed 95% CL upper limits on $|V_\mathrm{N}|^2$ as a function of $m_\mathrm{N}$ for the mixing scenario ($r_e$, $r_\mu$, $r_\tau$) = (0.0, 1.0, 0.0) and in the Majorana scenario.

Expected and observed 95% CL upper limits on $|V_\mathrm{N}|^2$ as a function of $m_\mathrm{N}$ for the mixing scenario ($r_e$, $r_\mu$, $r_\tau$) = (0.0, 0.5, 0.5) and in the Majorana scenario.

Expected and observed 95% CL upper limits on $|V_\mathrm{N}|^2$ as a function of $m_\mathrm{N}$ for the mixing scenario ($r_e$, $r_\mu$, $r_\tau$) = (0.5, 0.5, 0.0) and in the Majorana scenario.

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Measurement of $t$-channel production of single top quarks and antiquarks in $pp$ collisions at 13 TeV using the full ATLAS Run 2 data sample

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
CERN-EP-2023-289, 2024.
Inspire Record 2764820 DOI 10.17182/hepdata.150693

The production of single top quarks and top antiquarks via the $t$-channel exchange of a virtual $W$ boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the LHC using $140\,\mathrm{fb^{-1}}$ of ATLAS data. The total cross-sections are determined to be $\sigma(tq)=137^{+8}_{-8}\,\mathrm{pb}$ and $\sigma(\bar{t}q)=84^{+6}_{-5}\,\mathrm{pb}$ for top-quark and top-antiquark production, respectively. The combined cross-section is found to be $\sigma(tq+\bar{t}q)=221^{+13}_{-13}\,\mathrm{pb}$ and the cross-section ratio is $R_{t}=\sigma(tq)/\sigma(\bar{t}q)=1.636^{+0.036}_{-0.034}$. The predictions at next-to-next-to-leading-order in quantum chromodynamics are in good agreement with these measurements. The predicted value of $R_{t}$ using different sets of parton distribution functions is compared with the measured value, demonstrating the potential to further constrain the functions when using this result in global fits. The measured cross-sections are interpreted in an effective field theory approach, setting limits at the 95% confidence level on the strength of a four-quark operator and an operator coupling the third quark generation to the Higgs boson doublet: $-0.37 < C_{Qq}^{3,1}/\Lambda^2 < 0.06$ and $-0.87 < C_{\phi Q}^{3}/\Lambda^2 < 1.42$. The constraint $|V_{tb}|>0.95$ at the 95% confidence level is derived from the measured value of $\sigma(tq+\bar{t}q)$. In a more general approach, pairs of CKM matrix elements involving top quarks are simultaneously constrained, leading to confidence contours in the corresponding two-dimensional parameter spaces.

21 data tables

The 17 variables used for the training of the NN ordered by their discriminating power. The jet that is not \(b\)-tagged is referred to as the untagged jet. The charged lepton is denoted \(\ell\). The sphericity tensor \(S^{\alpha\beta}\) used to define the sphericity \(S\) is formed with the three-momenta \(\vec{p}_i\) of the reconstructed objects, namely the jets, the charged lepton and the reconstructed neutrino. The tensor is given by \(S^{\alpha\beta}=\frac{\sum_i p_i^\alpha p_i^\beta}{\sum_i |\vec{p}_i|^2}\) where \(\alpha\) and \(\beta\) correspond to the spatial components $x$, $y$ and $z$.

The impact of different groups of systematic uncertainties on the \(\sigma(tq)\) , \(\sigma(\bar t q)\), \(\sigma(tq + \bar t q)\) and \(R_t\), given in %.

The impact of the eight most important systematic uncertainties on the \(\sigma(tq)\) , \(\sigma(\bar t q)\) and \(\sigma(tq + \bar t q)\), given in %. The sequence of the uncertainties is given by the impact on \(\sigma(tq + \bar t q)\)

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Searches for exclusive Higgs boson decays into $D^*\gamma$ and $Z$ boson decays into $D^0\gamma$ and $K^0_s\gamma$ in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2024-037, 2024.
Inspire Record 2763131 DOI 10.17182/hepdata.147194

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 ${\cal B}(Z\rightarrow K^0_s\gamma)< 3.1 (3.0)\times 10^{-6}$.

2 data tables

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.


New constraints on ultraheavy dark matter from the LZ experiment

The LZ collaboration Aalbers, J. ; Akerib, D.S. ; Al Musalhi, A.K. ; et al.
FERMILAB-PUB-24-0015-TD, 2024.
Inspire Record 2758452 DOI 10.17182/hepdata.151392

Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/$c^2$ to a few TeV/$c^2$. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a re-analysis of the first science run (SR1) of the LZ experiment, with an exposure of $0.9$ tonne$\times$year, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 10$^{17}$ GeV/$c^2$.

5 data tables

Upper limit on the WIMP-nucleon scattering cross section from the multiple-scatter analysis.

Upper limit on the WIMP-nucleus scattering cross section from the multiple-scatter analysis.

Upper limit on the WIMP-nucleon scattering cross section from the single-scatter analysis.

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ATLAS Run 2 searches for electroweak production of supersymmetric particles interpreted within the pMSSM

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
CERN-EP-2024-021, 2024.
Inspire Record 2755168 DOI 10.17182/hepdata.149493

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.

2 data tables

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.


Search for pair production of higgsinos in events with two Higgs bosons and missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions at the ATLAS experiment

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
CERN-EP-2023-278, 2024.
Inspire Record 2751932 DOI 10.17182/hepdata.136030

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.

66 data tables

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.

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