A search for diphoton resonances in the mass range between 10 and 70 GeV with the ATLAS experiment at the Large Hadron Collider (LHC) is presented. The analysis is based on $pp$ collision data corresponding to an integrated luminosity of 138 fb$^{-1}$ at a centre-of-mass energy of 13 TeV recorded from 2015 to 2018. Previous searches for diphoton resonances at the LHC have explored masses down to 65 GeV, finding no evidence of new particles. This search exploits the particular kinematics of events with pairs of closely spaced photons reconstructed in the detector, allowing examination of invariant masses down to 10 GeV. The presented strategy covers a region previously unexplored at hadron colliders because of the experimental challenges of recording low-energy photons and estimating the backgrounds. No significant excess is observed and the reported limits provide the strongest bound on promptly decaying axion-like particles coupling to gluons and photons for masses between 10 and 70 GeV.
The expected and observed upper limits at 95\% CL on the fiducial cross-section times branching ratio to two photons of a narrow-width ($\Gamma_{X}$ = 4 MeV) scalar resonance as a function of its mass $m_{X}$.
Diphoton invariant mass in the signal region using a 0.1 GeV binning.
Parametrization of the $C_{X}$ factor, defined as the ratio between the number of reconstructed signal events passing the analysis cuts and the number of signal events at the particle level generated within the fiducial volume, as function of $m_{X}$ obtained from the narrow width simulated signal samples produced in gluon fusion.
A search for light long-lived neutral particles with masses in the $O$(MeV-GeV) range is presented. The analysis targets the production of long-lived dark photons in the decay of a Higgs boson produced via gluon-gluon fusion or in association with a $W$ boson. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are selected in 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV $pp$ collision data collected by the ATLAS detector at the LHC. Background estimates for contributions from Standard Model processes and instrumental effects are extracted from data. The observed event yields are consistent with the expected background. Exclusion limits are reported on the production cross-section times branching fraction as a function of the mean proper decay length $c\tau$ of the dark photon, or as a function of the dark-photon mass and kinetic mixing parameter that quantifies the coupling between the Standard Model and potential hidden (dark) sectors. A Higgs boson branching fraction above 1% is excluded at 95% CL for a Higgs boson decaying into two dark photons for dark-photon mean proper decay lengths between 10 mm and 250 mm and dark photons with masses between 0.4 GeV and 2 GeV.
The reconstruction efficiency for μDPJ objects satisfying the cosmic-ray tagger selection produced in the decay of a γ<sub>d</sub> into a muon pair. The reconstruction efficiency is shown for γ<sub>d</sub> with 0<|η|<1 as a function of the transverse decay length L<sub>xy</sub>.
The reconstruction efficiency for μDPJ objects satisfying the cosmic-ray tagger selection produced in the decay of a γ<sub>d</sub> into a muon pair. The reconstruction efficiency is shown for γ<sub>d</sub> with 0<|η|<1 as a function of the γ<sub>d</sub> transverse momentum in events where the γ<sub>d</sub> L<sub>xy</sub> is below 6 m.
The reconstruction efficiency for caloDPJs produced by the decay of γ<sub>d</sub> into e<sup>+</sup>e<sup>-</sup> or qq̄. The reconstruction efficiency is shown for γ<sub>d</sub> with 0<|η|<1.1 as a function of the transverse decay length L<sub>xy</sub>. The efficiency drop at 2.5 m corresponds to the end of the first layer of the HCAL.
A search for forward proton scattering in association with light-by-light scattering mediated by an axion-like particle is presented, using the ATLAS Forward Proton spectrometer to detect scattered protons and the central ATLAS detector to detect pairs of outgoing photons. Proton-proton collision data recorded in 2017 at a centre-of-mass energy of $\sqrt{s} = 13$ TeV were analysed, corresponding to an integrated luminosity of 14.6 fb$^{-1}$. A total of 441 candidate signal events were selected. A search was made for a narrow resonance in the diphoton mass distribution, corresponding to an axion-like particle (ALP) with mass in the range 150-1600 GeV. No excess is observed above a smooth background. Upper limits on the production cross section of a narrow resonance are set as a function of the mass, and are interpreted as upper limits on the ALP production coupling constant, assuming 100% decay branching ratio into a photon pair. The inferred upper limit on the coupling constant is in the range 0.04-0.09 TeV$^{-1}$ at 95%confidence level.
Signal selection efficiency as a function of ALP mass $m_{\textrm{X}}$ for the exclusive (EL), single-dissociative (SD), and double-dissociative (DD) processes. The ratio of the number of selected events to the number of generated MC events is given (black points) and is parameterised by an analytic function (red solid line). The linear (black dashed line) and cubic (blue chain line) interpolations of the black points are used to derive the envelopes (cyan filled region) which are regarded as systematic uncertainties.
The diphoton mass distribution of the mixed-data sample (black points).
The $(\xi_{\gamma\gamma}^{+},\xi_{\gamma\gamma}^{-})$ distribution of the selected data candidates after the full event selection in $m_{\gamma\gamma}$ in [150,1600] GeV with $m_{\gamma\gamma}$ contours (blue) and $y_{\gamma\gamma}$ contours (black). The range of $\xi_{\gamma\gamma}$ in which forward-proton matching is possible, $[0.035-\xi_{\textrm{th}}, 0.08+\xi_{\textrm{th}} ]$, for events that pass the matching requirement to the A or C side as indicated. No event passed the matching requirement for both the A-side and C-side.
A search for flavor-changing neutral-current couplings between a top quark, an up or charm quark and a $Z$ boson is presented, using proton-proton collision data at $\sqrt{s} = 13$ TeV collected by the ATLAS detector at the Large Hadron Collider. The analyzed dataset corresponds to an integrated luminosity of 139 fb$^{-1}$. The search targets both single-top-quark events produced as $gq\rightarrow tZ$ (with $q = u, c$) and top-quark-pair events, with one top quark decaying through the $t \rightarrow Zq$ channel. The analysis considers events with three leptons (electrons or muons), a $b$-tagged jet, possible additional jets, and missing transverse momentum. The data are found to be consistent with the background-only hypothesis and 95% confidence-level limits on the $t \rightarrow Zq$ branching ratios are set, assuming only tensor operators of the Standard Model effective field theory framework contribute to the $tZq$ vertices. These are $6.2 \times 10^{-5}$ ($13\times 10^{-5}$) for $t\rightarrow Zu$ ($t\rightarrow Zc$) for a left-handed $tZq$ coupling, and $6.6 \times 10^{-5}$ ($12\times 10^{-5}$) in the case of a right-handed coupling. These results are interpreted as 95% CL upper limits on the strength of corresponding couplings, yielding limits for $|C_{uW}^{(13)*}|$ and $|C_{uB}^{(13)*}|$ ($|C_{uW}^{(31)}|$ and $|C_{uB}^{(31)}|$) of 0.15 (0.16), and limits for $|C_{uW}^{(23)*}|$ and $|C_{uB}^{(23)*}|$ ($|C_{uW}^{(32)}|$ and $|C_{uB}^{(32)}|$) of 0.22 (0.21), assuming a new-physics energy scale $\Lambda_\text{NP}$ of 1 TeV.
Summary of the signal strength $\mu$ parameters obtained from the fits to extract LH and RH results for the FCNC tZu and tZc couplings. For the reference branching ratio, the most stringent limits are used.
Observed and expected 95% CL limits on the FCNC $t\rightarrow Zq$ branching ratios and the effective coupling strengths for different vertices and couplings (top eight rows). For the latter, the energy scale is assumed to be $\Lambda_{NP}$ = 1 TeV. The bottom rows show, for the case of the FCNC $t\rightarrow Zu$ branching ratio, the observed and expected 95% CL limits when only one of the two SRs, either SR1 or SR2, and all CRs are included in the likelihood.
Comparison between data and background prediction before the fit (Pre-Fit) for the mass of the SM top-quark candidate in SR1. The uncertainty band includes both the statistical and systematic uncertainties in the background prediction. The four FCNC LH signals are also shown separately, normalized to five times the cross-section corresponding to the most stringent observed branching ratio limits. The first (last) bin in all distributions includes the underflow (overflow). The lower panels show the ratios of the data (Data) to the background prediction (Bkg.).
Differential cross-section measurements of $Z\gamma$ production in association with hadronic jets are presented, using the full 139 fb$^{-1}$ dataset of $\sqrt{s}=13$ TeV proton-proton collisions collected by the ATLAS detector during Run 2 of the LHC. Distributions are measured using events in which the $Z$ boson decays leptonically and the photon is usually radiated from an initial-state quark. Measurements are made in both one and two observables, including those sensitive to the hard scattering in the event and others which probe additional soft and collinear radiation. Different Standard Model predictions, from both parton-shower Monte Carlo simulation and fixed-order QCD calculations, are compared with the measurements. In general, good agreement is observed between data and predictions from MATRIX and MiNNLO$_\text{PS}$, as well as next-to-leading-order predictions from MadGraph5_aMC@NLO and Sherpa.
Measured differential cross section as a function of observable $ p_{T}^{ll}$. Error on the measured cross-section include all the systematic uncertainties. SM predictions are produced with the event generators at particle level: Sherpa 2.2.4, Sherpa 2.2.11, MadGraph5_aMC@NLO, and MiNNLO$_{PS}$. Fixed order calculations results use MATRIX NNLO. Error represent statistical uncertainty and theoretical uncertainty (PDF and Scale variations).
Measured differential cross section as a function of observable $ p_{T}^{ll}$. Error on the measured cross-section include all the systematic uncertainties. SM predictions are produced with the event generators at particle level: Sherpa 2.2.4, Sherpa 2.2.11, MadGraph5_aMC@NLO, and MiNNLO$_{PS}$. Fixed order calculations results use MATRIX NNLO. Error represent statistical uncertainty and theoretical uncertainty (PDF and Scale variations).
Measured differential cross section as a function of observable $ p_{T}^{ll} - p_{T}^{\gamma}$. Error on the measured cross-section include all the systematic uncertainties. SM predictions are produced with the event generators at particle level: Sherpa 2.2.4, Sherpa 2.2.11, MadGraph5_aMC@NLO, and MiNNLO$_{PS}$. Fixed order calculations results use MATRIX NNLO. Error represent statistical uncertainty and theoretical uncertainty (PDF and Scale variations).
A search for pair-produced scalar or vector leptoquarks decaying into a $b$-quark and a $\tau$-lepton is presented using the full LHC Run 2 (2015-2018) data sample of 139 fb$^{-1}$ collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} =13$ TeV. Events in which at least one $\tau$-lepton decays hadronically are considered, and multivariate discriminants are used to extract the signals. No significant deviations from the Standard Model expectation are observed and 95% confidence-level upper limits on the production cross-section are derived as a function of leptoquark mass and branching ratio $B$ into a $\tau$-lepton and $b$-quark. For scalar leptoquarks, masses below 1460 GeV are excluded assuming $B=100$%, while for vector leptoquarks the corresponding limit is 1650 GeV (1910 GeV) in the minimal-coupling (Yang-Mills) scenario.
Acceptance $\times$ efficiency for the $\tau_\text{lep}\tau_\text{had}$ signal region assuming $\beta$ = 0.5 as a function of m$_\text{LQ}$.
Acceptance $\times$ efficiency for the $\tau_\text{had}\tau_\text{had}$ signal region assuming $\beta$ = 0.5 as a function of m$_\text{LQ}$.
The observed and expected 95% CL upper limits on the scalar LQ pair production cross-sections assuming B = 1 as a function of m$_\text{LQ}$.
Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs ($t\bar{t}$) are measured using the full LHC Run 2 data sample collected with the ATLAS detector. The data were collected at a $pp$ collision energy of $\sqrt{s}=13$ TeV and correspond to an integrated luminosity of 140 fb$^{-1}$. The measurements use events containing an oppositely charged $e\mu$ pair and $b$-tagged jets. The results are compared with predictions from several Monte Carlo generators. While no prediction is found to be consistent with all distributions, a better agreement with measurements of the lepton $p_{\text{T}}$ distributions is obtained by reweighting the $t\bar{t}$ sample so as to reproduce the top-quark $p_{\text{T}}$ distribution from an NNLO calculation. The inclusive top-quark pair production cross-section is measured as well, both in a fiducial region and in the full phase-space. The total inclusive cross-section is found to be \[ \sigma_{t\bar{t}} = 829 \pm 1\;(\textrm{stat}) \pm 13\;(\textrm{syst}) \pm 8\;(\textrm{lumi}) \pm 2\; (\textrm{beam})\ \textrm{pb}, \] where the uncertainties are due to statistics, systematic effects, the integrated luminosity and the beam energy. This is in excellent agreement with the theoretical expectation.
Definition of the fiducial phase space with the lepton candidate, electron $e$ and muon $\mu$, and jets.
Breakdown of systematic uncertainties in the measured fiducial cross-section. The impact of the top-quark mass on the cross-section is included in the table and not counted in the total uncertainty entry in the paper.
Data bootstrap post unfolding for the fiducial cross-section. The replicas are obtained by reweighting each observed data event by a random integer generated according to Poisson statistics, using the BootstrapGenerator software package (https://gitlab.cern.ch/atlas-physics/sm/StandardModelTools_BootstrapGenerator/BootstrapGenerator), which implements a technique described in ATL-PHYS-PUB-2021-011 (https://cds.cern.ch/record/2759945). The ATLAS event number and run number of each event are used as seed to uniquely but reproducibly initialise the random number generator for each event. All the provided numbers originate from pseudo-data, including the 0th entry, and are in units of [fb].
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>
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.
This paper presents a measurement of fiducial and differential cross-sections for $W^{+}W^{-}$ production in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS experiment at the Large Hadron Collider using a dataset corresponding to an integrated luminosity of 139 fb$^{-1}$. Events with exactly one electron, one muon and no hadronic jets are studied. The fiducial region in which the measurements are performed is inspired by searches for the electroweak production of supersymmetric charginos decaying to two-lepton final states. The selected events have moderate values of missing transverse momentum and the `stransverse mass' variable $m_{\textrm{T2}}$, which is widely used in searches for supersymmetry at the LHC. The ranges of these variables are chosen so that the acceptance is enhanced for direct $W^{+}W^{-}$ production and suppressed for production via top quarks, which is treated as a background. The fiducial cross-section and particle-level differential cross-sections for six variables are measured and compared with two theoretical SM predictions from perturbative QCD calculations.
Signal region detector-level distribution for the observable $|y_{e\mu}|$.
Signal region detector-level distribution for the observable $|\Delta \phi(e \mu)|$.
Signal region detector-level distribution for the observable $ \cos\theta^{\ast}$.
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