1,721,389 research outputs found
Search for the HH -> b(b)over-barb(b)over-bar process via vector-boson fusion production using proton-proton collisions at root s = 13 TeV with the ATLAS detector (vol 7, 108, 2020)
No full textOne correction is noted for the paper. © 2021, The Author(s)
Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb(-1) of Pb+Pb data with the ATLAS detector (vol 2021, 243, 2021)
No full textOne correction is noted for the paper, which does not affect the results reported. The right panel of figure 9 is corrected as it contained the 'internal' label, giving the misleading impression on the credibility of the figure. © 2021, The Author(s)
Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at = 13 TeV with the ATLAS detector
Full text linkA measurement of the top-quark mass (mt) in the tt ̄ → lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass mlμ of the lepton, l (with l = e, μ), from the W-boson decay and the muon, μ, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb−1 of s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 ± 0.39 (stat.) ± 0.66 (syst.) ± 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup. [Figure not available: see fulltext.]. © 2023, The Author(s)
Measurement of single top-quark production in the s-channel in proton–proton collisions at = 13 TeV with the ATLAS detector
Full text linkA measurement of single top-quark production in the s-channel is performed in proton–proton collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The dataset corresponds to an integrated luminosity of 139 fb −1. The analysis is performed on events with an electron or muon, missing transverse momentum and exactly two b-tagged jets in the final state. A discriminant based on matrix element calculations is used to separate single-top-quark s-channel events from the main background contributions, which are top-quark pair production and W-boson production in association with jets. The observed (expected) signal significance over the background-only hypothesis is 3.3 (3.9) standard deviations, and the measured cross-section is σ=8.2−2.9+3.5 pb, consistent with the Standard Model prediction of σSM=10.32−0.36+0.40 pb. [Figure not available: see fulltext.] © 2023, The Author(s)
Search for heavy, long-lived, charged particles with large ionisation energy loss in pp collisions at = 13 TeV using the ATLAS experiment and the full Run 2 dataset
Full text linkThis paper presents a search for hypothetical massive, charged, long-lived particles with the ATLAS detector at the LHC using an integrated luminosity of 139 fb−1 of proton–proton collisions at s = 13 TeV. These particles are expected to move significantly slower than the speed of light and should be identifiable by their high transverse momenta and anomalously large specific ionisation losses, dE/dx. Trajectories reconstructed solely by the inner tracking system and a dE/dx measurement in the pixel detector layers provide sensitivity to particles with lifetimes down to O (1) ns with a mass, measured using the Bethe–Bloch relation, ranging from 100 GeV to 3 TeV. Interpretations for pair-production of R-hadrons, charginos and staus in scenarios of supersymmetry compatible with these particles being long-lived are presented, with mass limits extending considerably beyond those from previous searches in broad ranges of lifetime. [Figure not available: see fulltext.] © 2023, The Author(s)
Measurement of the Higgs boson mass in the H → ZZ⁎ → 4l decay channel using 139 fb−1 of s=13 TeV pp collisions recorded by the ATLAS detector at the LHC
Full text linkThe mass of the Higgs boson is measured in the H→ZZ⁎→4l decay channel. The analysis uses proton–proton collision data from the Large Hadron Collider at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector between 2015 and 2018, corresponding to an integrated luminosity of 139 fb−1. The measured value of the Higgs boson mass is 124.99±0.18(stat.)±0.04(syst.) GeV. In final states with muons, this measurement benefits from an improved momentum-scale calibration relative to that adopted in previous publications. The measurement also employs an analytic model that takes into account the invariant-mass resolution of the four-lepton system on a per-event basis and the output of a deep neural network discriminating signal from background events. This measurement is combined with the corresponding measurement using 7 and 8 TeV pp collision data, resulting in a Higgs boson mass of 124.94±0.17(stat.)±0.03(syst.) GeV. © 2023 The Author(s
Search for resonant WZ production in the fully leptonic final state in proton–proton collisions at TeV with the ATLAS detector
No full textA search for a WZ resonance, in the fully leptonic final state (electrons or muons), is performed using 139 fb - 1 of data collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The results are interpreted in terms of a singly charged Higgs boson of the Georgi–Machacek model, produced by WZ fusion, and of a Heavy Vector Triplet, with the resonance produced by WZ fusion or the Drell–Yan process. No significant excess over the Standard Model prediction is observed and limits are set on the production cross-section times branching ratio as a function of the resonance mass for these processes. © 2023, The Author(s)
Measurement of Zγγ production in pp collisions at √s=13 TeV with the ATLAS detector
Full text linkCross-sections for the production of a Z boson in association with two photons are measured in proton–proton collisions at a centre-of-mass energy of 13 TeV. The data used correspond to an integrated luminosity of 139 fb - 1 recorded by the ATLAS experiment during Run 2 of the LHC. The measurements use the electron and muon decay channels of the Z boson, and a fiducial phase-space region where the photons are not radiated from the leptons. The integrated Z(→ ll) γγ cross-section is measured with a precision of 12% and differential cross-sections are measured as a function of six kinematic variables of the Zγγ system. The data are compared with predictions from MC event generators which are accurate to up to next-to-leading order in QCD. The cross-section measurements are used to set limits on the coupling strengths of dimension-8 operators in the framework of an effective field theory. © 2023, The Author(s)
Search for pair production of third-generation leptoquarks decaying into a bottom quark and a -lepton with the ATLAS detector
Full text linkA search for pair-produced scalar or vector leptoquarks decaying into a b-quark and a τ -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 s=13 TeV. Events in which at least one τ -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 τ -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. © 2023, The Author(s)
Measurements of Zγ+jets differential cross sections in pp collisions at = 13 TeV with the ATLAS detector
Full text linkDifferential cross-section measurements of Zγ production in association with hadronic jets are presented, using the full 139 fb −1 dataset of 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 MiNNLOPS, as well as next-to-leading-order predictions from MadGraph5_aMC@NLO and Sherpa. [Figure not available: see fulltext.] © 2023, The Author(s)
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