A search for physics beyond the standard model (SM) in final states with an electron or muon and missing transverse momentum is presented. The analysis uses data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected with the CMS detector at the LHC in 2016–2018 and corresponding to an integrated luminosity of 138 fb−1. No significant deviation from the SM prediction is observed. Model-independent limits are set on the production cross section of W’ bosons decaying into lepton-plus-neutrino final states. Within the framework of the sequential standard model, with the combined results from the electron and muon decay channels a W’ boson with mass less than 5.7 TeV is excluded at 95% confidence level. Results on a SM precision test, the determination of the oblique electroweak W parameter, are presented using LHC data for the first time. These results together with those from the direct W’ resonance search are used to extend existing constraints on composite Higgs scenarios. This is the first experimental exclusion on compositeness parameters using results from LHC data other than Higgs boson measurements.
A search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state is presented. The analysis is based on proton-proton collision data recorded by the CMS detector in 2016-2018 at a centre-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. The search is sensitive to resonances with masses between 1.3 and 6 TeV, decaying to bosons that are highly Lorentz-boosted such that each of the bosons forms a single large-radius jet. Machine learning techniques are employed to identify such jets. No significant excess over the estimated standard model background is observed. A maximum local significance of 3.6 standard deviations, corresponding to a global significance of 2.3 standard deviations, is observed at masses of 2.1 and 2.9 TeV. In a heavy vector triplet model, spin-1 Z' and W' resonances with masses below 4.8 TeV are excluded at the 95% confidence level (CL). These limits are the most stringent to date. In a bulk graviton model, spin-2 gravitons and spin-0 radions with masses below 1.4 and 2.7 TeV, respectively, are excluded at 95% CL. Production of heavy resonances through vector boson fusion is constrained with upper cross section limits at 95% CL as low as 0.1 fb.
Results of a search for new physics in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 139 fb$^{-1}$ at a center-of-mass energy of 13 TeV collected in the period 2015-2018 with the ATLAS detector at the Large Hadron Collider. Compared to previous publications, in addition to an increase of almost a factor of four in the data size, the analysis implements a number of improvements in the signal selection and the background determination leading to enhanced sensitivity. Events are required to have at least one jet with transverse momentum above 150 GeV and no reconstructed leptons ($e$, $\mu$ or $\tau$) or photons. Several signal regions are considered with increasing requirements on the missing transverse momentum starting at 200 GeV. Overall agreement is observed between the number of events in data and the Standard Model predictions. Model-independent 95 % confidence-level limits on visible cross sections for new processes are obtained in the range between 736 fb and 0.3 fb with increasing missing transverse momentum. Results are also translated into improved exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, supersymmetric particles in several compressed scenarios, axion-like particles, and new scalar particles in dark-energy-inspired models. In addition, the data are translated into bounds on the invisible branching ratio of the Higgs boson.
- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Post-fit $p_{\mathrm{T}}^{\mathrm{recoil}}$ distribution:</b> <ul> <li><a href="102093?version=1&table=HistogramCR1mu0b">CR1mu0b</a> <li><a href="102093?version=1&table=HistogramCR1e0b">CR1e0b</a> <li><a href="102093?version=1&table=HistogramCR1L1b">CR1L1b</a> <li><a href="102093?version=1&table=HistogramCR2mu">CR2mu</a> <li><a href="102093?version=1&table=HistogramCR2e">CR2e</a> <li><a href="102093?version=1&table=HistogramSR">SR</a> </ul> <b>Exclusion contours:</b> <ul> <li>Dark Matter axial-vector mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMA">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMA">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMA">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMA">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMA">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMA">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMA">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMA">-2 $\sigma$ expected</a> </ul> <li>Dark Matter pseudo-scalar mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMP">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMP">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMP">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMP">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMP">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMP">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMP">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMP">-2 $\sigma$ expected</a> </ul> <li>Dark Matter vector mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMV">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMV">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMV">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMV">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMV">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMV">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMV">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMV">-2 $\sigma$ expected</a> </ul> <li>Dark Matter spin-dependent WIMP-nucleon scattering cross-section: <a href="102093?version=1&table=ContourSDneutron">observed</a> <li>Dark Matter spin-independent WIMP-nucleon scattering cross-section: <a href="102093?version=1&table=ContourSInucleon">observed</a> <li>Dark Matter WIMP annihilation rate: <a href="102093?version=1&table=ContourID">observed</a> <li>SUSY stop pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsTT_directCC">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1TT_directCC">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1TT_directCC">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expTT_directCC">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1TT_directCC">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1TT_directCC">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2TT_directCC">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2TT_directCC">-2 $\sigma$ expected</a> </ul> <li>SUSY stop pair production (4-body decay): <ul> <li><a href="102093?version=1&table=Contourg_obsTT_bffN">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1TT_bffN">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1TT_bffN">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expTT_bffN">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1TT_bffN">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1TT_bffN">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2TT_bffN">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2TT_bffN">-2 $\sigma$ expected</a> </ul> <li>SUSY sbottom pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsBB">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1BB">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1BB">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expBB">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1BB">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1BB">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2BB">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2BB">-2 $\sigma$ expected</a> </ul> <li>SUSY squark pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsSS">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1SS">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1SS">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expSS">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1SS">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1SS">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2SS">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2SS">-2 $\sigma$ expected</a> </ul> <li>Dark energy: <a href="102093?version=1&table=ContourDE">observed and expected</a> <li>ADD: <a href="102093?version=1&table=ContourADD">observed and expected</a> <li>Axion-like particles: <a href="102093?version=1&table=ContourALPs">observed and expected</a> </ul> <b>Impact of systematic uncertainties:</b> <a href="102093?version=1&table=Tablesystimpacts">Table</a><br/><br/> <b>Yields of exclusive regions:</b> <a href="102093?version=1&table=TableyieldsEM0">EM0</a> <a href="102093?version=1&table=TableyieldsEM1">EM1</a> <a href="102093?version=1&table=TableyieldsEM2">EM2</a> <a href="102093?version=1&table=TableyieldsEM3">EM3</a> <a href="102093?version=1&table=TableyieldsEM4">EM4</a> <a href="102093?version=1&table=TableyieldsEM5">EM5</a> <a href="102093?version=1&table=TableyieldsEM6">EM6</a> <a href="102093?version=1&table=TableyieldsEM7">EM7</a> <a href="102093?version=1&table=TableyieldsEM8">EM8</a> <a href="102093?version=1&table=TableyieldsEM9">EM9</a> <a href="102093?version=1&table=TableyieldsEM10">EM10</a> <a href="102093?version=1&table=TableyieldsEM11">EM11</a> <a href="102093?version=1&table=TableyieldsEM12">EM12</a><br/><br/> <b>Yields of inclusive regions:</b> <a href="102093?version=1&table=TableyieldsIM0">IM0</a> <a href="102093?version=1&table=TableyieldsIM1">IM1</a> <a href="102093?version=1&table=TableyieldsIM2">IM2</a> <a href="102093?version=1&table=TableyieldsIM3">IM3</a> <a href="102093?version=1&table=TableyieldsIM4">IM4</a> <a href="102093?version=1&table=TableyieldsIM5">IM5</a> <a href="102093?version=1&table=TableyieldsIM6">IM6</a> <a href="102093?version=1&table=TableyieldsIM7">IM7</a> <a href="102093?version=1&table=TableyieldsIM8">IM8</a> <a href="102093?version=1&table=TableyieldsIM9">IM9</a> <a href="102093?version=1&table=TableyieldsIM10">IM10</a> <a href="102093?version=1&table=TableyieldsIM11">IM11</a> <a href="102093?version=1&table=TableyieldsIM12">IM12</a><br/><br/> <b>Cutflows:</b><br/><br/> Signals filtered with a truth $E_\mathrm{T}^\mathrm{miss}$ cut at: <ul> <li> <a href="102093?version=1&table=Tablecutflows150GeV">150 GeV</a> <li> <a href="102093?version=1&table=Tablecutflows350GeV">350 GeV</a> </ul>
A comparison of the inferred limits with the constraints from direct-detection experiments on the spin-dependent WIMP-neutron and WIMP-proton scattering cross section as a function of the WIMP mass, in the context of the simplified model with axial-vector couplings. Limits are shown at 90% CL.
A comparison of the inferred limits with the constraints from direct-detection experiments on the spin-independent WIMP-nucleon scattering cross section as a function of the WIMP mass, in the context of the simplified model with vector couplings. Limits are shown at 90% CL.
This paper presents measurements of $W^{\pm}Z$ production cross sections in $pp$ collisions at a centre-of-mass energy of 13 TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 36.1 fb$^{-1}$. The $W^{\pm}Z$ candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The measured inclusive cross section in the detector fiducial region for a single leptonic decay mode is $\sigma_{W^\pm Z \rightarrow \ell^{'} \nu \ell \ell}^{\textrm{fid.}} = 63.7 \pm 1.0$ (stat.) $\pm 2.3$ (syst.) $\pm 1.4$ (lumi.) fb, reproduced by the next-to-next-to-leading-order Standard Model prediction of $61.5^{+1.4}_{-1.3}$ fb. Cross sections for $W^+Z$ and $W^-Z$ production and their ratio are presented as well as differential cross sections for several kinematic observables. An analysis of angular distributions of leptons from decays of $W$ and $Z$ bosons is performed for the first time in pair-produced events in hadronic collisions, and integrated helicity fractions in the detector fiducial region are measured for the $W$ and $Z$ bosons separately. Of particular interest, the longitudinal helicity fraction of pair-produced vector bosons is also measured.
Measured fiducial cross section for a single leptonic decay channel $\ell'^\pm \nu \ell^+ \ell'^-$ of the $W The relative uncertainties are reported as percentages. The systematic uncertainties are in order of appearance: total uncorrelated systematic and correlated systematics related respectively to unfolding, electrons, muons, jets, reducible and irreducible backgrounds and pileup. the last bin is a cross section for all events above the lower end of the bin.
This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy $\sqrt{s} = 13$ TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the bbbb, bbWW, bb$\tau\tau$, WWWW, bb$\gamma \gamma$ and WW$\gamma\gamma$ final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio ($ \kappa_{\lambda} $) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to $ -5.0 < \kappa_{\lambda} <12.0 $ ($ -5.8 < \kappa_{\lambda} <12.0 $). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model.
Signal acceptance times efficiency as a function of κ<sub>λ</sub> for the $b\bar{b}b\bar{b}$, $b\bar{b}\tau^{+}\tau^{-}$ and $b\bar{b}\gamma\gamma$ analyses. The $b\bar{b}b\bar{b}$ curve is the average of the 2015 and 2016 curves weighted by the integrated luminosities of the two datasets
Upper limits at 95% CL on the cross-section of the ggF non-resonant SM HH production as a function of κ<sub>λ</sub>. The observed (expected) limits are shown as solid (dashed) lines. In the $b\bar{b}\gamma\gamma$ final state, the observed and expected limits coincide. The $\pm 1 \sigma$ and $\pm 2\sigma$ bands are only shown for the combined expected limit. The theoretical prediction of the cross-section as a function of κ<sub>λ</sub> is also shown.
Upper limits at 95% CL on the cross-section of the resonant Higgs boson pair production for a spin-0 heavy scalar
Measurements of the azimuthal anisotropy in lead-lead collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV are presented using a data sample corresponding to 0.49 $\mathrm{nb}^{-1}$ integrated luminosity collected by the ATLAS experiment at the LHC in 2015. The recorded minimum-bias sample is enhanced by triggers for "ultra-central" collisions, providing an opportunity to perform detailed study of flow harmonics in the regime where the initial state is dominated by fluctuations. The anisotropy of the charged-particle azimuthal angle distributions is characterized by the Fourier coefficients, $v_{2}-v_{7}$, which are measured using the two-particle correlation, scalar-product and event-plane methods. The goal of the paper is to provide measurements of the differential as well as integrated flow harmonics $v_{n}$ over wide ranges of the transverse momentum, 0.5 $
The V3 harmonic measured with the scalar product method as a funtion of transverse momentum in centrality bin 70-80%
Azimuthal decorrelations between the two central jets with the largest transverse momenta are sensitive to the dynamics of events with multiple jets. We present a measurement of the normalized differential cross section based on the full dataset (L=36/pb) acquired by the ATLAS detector during the 2010 sqrt(s)=7 TeV proton-proton run of the LHC. The measured distributions include jets with transverse momenta up to 1.3 TeV, probing perturbative QCD in a high energy regime.
Distribution for the maxPT jet (P=3) from 110 to 160 GeV.
Distribution for the maxPT jet (P=3) from 160 to 210 GeV.
Distribution for the maxPT jet (P=3) from 210 to 260 GeV.
The inclusive J/psi production cross-section and fraction of J/psi mesons produced in B-hadron decays are measured in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the J/psi, using 2.3 pb-1 of integrated luminosity. The cross-section is measured from a minimum pT of 1 GeV to a maximum of 70 GeV and for rapidities within |y| < 2.4 giving the widest reach of any measurement of J/psi production to date. The differential production cross-sections of prompt and non-prompt J/psi are separately determined and are compared to Colour Singlet NNLO*, Colour Evaporation Model, and FONLL predictions.
Total cross section for inclusive andd non-prompt J/PSI (-> MU+MU-) production in the range |y| < 2.4 and pT > 7 GeV under the FLAT (ie isotropic) production scenario. The second (sys) error is the uncertainty assoicated with the spin and the third is the luminosity uncertainty.
Total cross section for inclusive and non-prompt J/PSI (-> MU+MU-) production in the range 1.5 < |y| < 2 and pT > 1 GeV under the FLAT (ie isotropic) production scenario. The second (sys) error is the uncertainty assoicated with the spin and the third is the luminosity uncertainty.
Inclusive J/psi production cross-section as a function of J/psi pT in the J/psi rapidity (|y|) bin 2<|y|<2.4. The first uncertainty is statistical, the second is systematic and the third encapsulates any possible variation due to spin-alignment from the unpolarised central value.
We present first measurements of charged and neutral particle-flow correlations in pp collisions using the ATLAS calorimeters. Data were collected in 2009 and 2010 at centre-of-mass energies of 900 GeV and 7 TeV. Events were selected using a minimum-bias trigger which required a charged particle in scintillation counters on either side of the interaction point. Particle flows, sensitive to the underlying event, are measured using clusters of energy in the ATLAS calorimeters, taking advantage of their fine granularity. No Monte Carlo generator used in this analysis can accurately describe the measurements. The results are independent of those based on charged particles measured by the ATLAS tracking systems and can be used to constrain the parameters of Monte Carlo generators.
900 GeV Particle density vs. Delta(phi) with leading particle pT > 1 GeV.
900 GeV Particle density vs. Delta(phi) with leading particle pT > 2 GeV.
900 GeV Particle density vs. Delta(phi) with leading particle pT > 3 GeV.
A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in sqrt(s) = 7 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 35 inverse picobarns of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with tan(beta)= 3, A_0=0 and mu>0, squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date.
The distribution in Meff (scalar sum of the missing transverse momentum and the transverse momenta of the two highest pT jets) for events with at least 2 jets after the application of all selection criteria (other than the Meff cut itself). The table shows the number of observed data points per 100 GeV bin plus the background prediction of the Standard-Model Monte-Carlo and its upper and lower 1-sigma error limits uncertainty band.
The distribution in Meff (scalar sum of the missing transverse momentum and the transverse momenta of the three highest pT jets) for events with at least 3 jets after the application of all selection criteria (other than the Meff cut itself). The table shows the number of observed data points per 100 GeV bin plus the background prediction of the Standard-Model Monte-Carlo and its upper and lower 1-sigma uncertainty band error limits.
The distribution in MT2 for events with at least 2 jets after the application of all selection criteria (other than the MT2 cut itself). The table shows the number of observed data points per 40 GeV bin plus the background prediction of the Standard-Model Monte-Carlo and its upper and lower 1-sigma uncertainty band error limits.
Forum