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Öğe Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery (Nature, (2022), 607, 7917, (52-59), 10.1038/s41586-022-04893-w)(Nature Research, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliCorrection to: Nature Published online 4 July 2022 In the version of this article initially published, the ATLAS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article. © 2023, The Author(s).Öğe Charged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at ?sNN = 5 TeV with the ATLAS detector at the LHC(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliThis paper presents measurements of charged-hadron spectra obtained in pp, p+Pb, and Pb+Pb collisions at s or sNN = 5.02 TeV, and in Xe+Xe collisions at sNN = 5.44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb?1, 28 nb?1, 0.50 nb?1, and 3 ?b?1, respectively. The nuclear modification factors RpPb and R AA are obtained by comparing the spectra in heavy-ion and pp collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor RpPb shows a moderate enhancement above unity with a maximum at p T ? 3 GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct p T-dependence with a local maximum at p T ? 2 GeV and a local minimum at p T ? 7 GeV. This dependence is more distinguishable in more central collisions. No significant |?|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe R AA better in central collisions and in the p T range from about 10 to 100 GeV. [Figure not available: see fulltext.] © 2023, The Author(s).Öğe Combination of searches for invisible decays of the Higgs boson using 139 fb?1 of proton-proton collision data at s=13 TeV collected with the ATLAS experiment(Elsevier B.V., 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliMany extensions of the Standard Model predict the production of dark matter particles at the LHC. Sufficiently light dark matter particles may be produced in decays of the Higgs boson that would appear invisible to the detector. This Letter presents a statistical combination of searches for H?invisible decays where multiple production modes of the Standard Model Higgs boson are considered. These searches are performed with the ATLAS detector using 139 fb?1 of proton–proton collisions at a centre–of–mass energy of [Formula presented] at the LHC. In combination with the results at [Formula presented] and [Formula presented], an upper limit on the H?invisible branching ratio of 0.107 (0.077) at the 95% confidence level is observed (expected). These results are also interpreted in the context of models where the 125 GeV Higgs boson acts as a portal to dark matter, and limits are set on the scattering cross-section of weakly interacting massive particles and nucleons. © 2023 The Author(s)Öğe A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery(Nature Research, 2022) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThe standard model of particle physics1–4 describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles5–9. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN10,11. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons—the carriers of the strong, electromagnetic and weak forces—are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (?)) are well measured and indications of interactions with a second-generation particle (muons, ?) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model. © 2022, The Author(s).Öğe Determination of the strong coupling constant from transverse energy-energy correlations in multijet events at ?s = 13 TeV with the ATLAS detector(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliMeasurements of transverse energy-energy correlations and their associated azimuthal asymmetries in multijet events are presented. The analysis is performed using a data sample corresponding to 139 fb?1 of proton-proton collisions at a centre-of-mass energy of s = 13 TeV, collected with the ATLAS detector at the Large Hadron Collider. The measurements are presented in bins of the scalar sum of the transverse momenta of the two leading jets and unfolded to particle level. They are then compared to next-to-next-to-leading-order perturbative QCD calculations for the first time, which feature a significant reduction in the theoretical uncertainties estimated using variations of the renormalisation and factorisation scales. The agreement between data and theory is good, thus providing a precision test of QCD at large momentum transfers Q. The strong coupling constant ?s is extracted as a function of Q, showing a good agreement with the renormalisation group equation and with previous analyses. A simultaneous fit to all transverse energy-energy correlation distributions across different kinematic regions yields a value of ?s(mZ)=0.1175±0.0006(exp.)?0.0017+0.0034(theo.) , while the global fit to the asymmetry distributions yields ?s(mZ)=0.1185±0.0009(exp.)?0.0012+0.0025(theo.) . [Figure not available: see fulltext.]. © 2023, The Author(s).Öğe Evidence for the Higgs boson decay to a Z boson and a photon at the LHC(American Physical Society, 2024) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThe first evidence for the Higgs boson decay to a Formula Presented boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around Formula Presented for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is Formula Presented times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations. © 2024 CERN, for the ATLAS and CMSs Collaboration.Öğe Inclusive and differential cross-sections for dilepton tt¯ production measured in ?s = 13 TeV pp collisions with the ATLAS detector(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliDifferential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs (tt¯) 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 s = 13 TeV and correspond to an integrated luminosity of 140 fb?1. The measurements use events containing an oppositely charged e? 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 T distributions is obtained by reweighting the tt¯ sample so as to reproduce the top-quark p 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 ?tt¯=829±1(stat)±13(syst)±8(lumi)±2(beam)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. [Figure not available: see fulltext.] © 2023, The Author(s).Öğe Inclusive-photon production and its dependence on photon isolation in pp collisions at ?s = 13 TeV using 139 fb?1 of ATLAS data(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliMeasurements of differential cross sections are presented for inclusive isolated-photon production in pp collisions at a centre-of-mass energy of 13 TeV provided by the LHC and using 139 fb?1 of data recorded by the ATLAS experiment. The cross sections are measured as functions of the photon transverse energy in different regions of photon pseudorapidity. The photons are required to be isolated by means of a fixed-cone method with two different cone radii. The dependence of the inclusive-photon production on the photon isolation is investigated by measuring the fiducial cross sections as functions of the isolation-cone radius and the ratios of the differential cross sections with different radii in different regions of photon pseudorapidity. The results presented in this paper constitute an improvement with respect to those published by ATLAS earlier: the measurements are provided for different isolation radii and with a more granular segmentation in photon pseudorapidity that can be exploited in improving the determination of the proton parton distribution functions. These improvements provide a more in-depth test of the theoretical predictions. Next-to-leading-order QCD predictions from JETPHOX and SHERPA and next-to-next-to-leading-order QCD predictions from NNLOJET are compared to the measurements, using several parameterisations of the proton parton distribution functions. The measured cross sections are well described by the fixed-order QCD predictions within the experimental and theoretical uncertainties in most of the investigated phase-space region. [Figure not available: see fulltext.] © 2023, The Author(s).Öğe Luminosity determination in pp collisions at ?s=13 TeV using the ATLAS detector at the LHC(Institute for Ionics, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliThe luminosity determination for the ATLAS detector at the LHC during Run 2 is presented, with pp collisions at a centre-of-mass energy s=13 TeV. The absolute luminosity scale is determined using van der Meer beam separation scans during dedicated running periods in each year, and extrapolated to the physics data-taking regime using complementary measurements from several luminosity-sensitive detectors. The total uncertainties in the integrated luminosity for each individual year of data-taking range from 0.9% to 1.1%, and are partially correlated between years. After standard data-quality selections, the full Run 2 pp data sample corresponds to an integrated luminosity of 140.1 ± 1.2 fb - 1 , i.e. an uncertainty of 0.83%. A dedicated sample of low-pileup data recorded in 2017–2018 for precision Standard Model physics measurements is analysed separately, and has an integrated luminosity of 338.1 ± 3.1 pb - 1 . © 2023, The Author(s).Öğe Measurement of exclusive pion pair production in proton–proton collisions at ?s=7TeV with the ATLAS detector(Institute for Ionics, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThe exclusive production of pion pairs in the process pp? pp?+?- has been measured at s=7TeV with the ATLAS detector at the LHC, using 80?b-1 of low-luminosity data. The pion pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion–pion invariant mass. Cross-section values of 4.8±1.0(stat)-0.2+0.3(syst)?b and 9±6(stat)-2+2(syst)?b are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type. © 2023, The Author(s).Öğe Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at ?sNN=5.02 TeV with the ATLAS Detector(American Physical Society, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThis letter presents a measurement of the nuclear modification factor of large-radius jets in Formula Presented Formula Presented collisions by the ATLAS experiment. The measurement is performed using Formula Presented and Formula Presented of Formula Presented and Formula Presented data, respectively. The large-radius jets are reconstructed with the anti-Formula Presented algorithm using a radius parameter of Formula Presented, by reclustering anti-Formula Presented Formula Presented jets, and are measured over the transverse momentum (Formula Presented) kinematic range of Formula Presented and absolute pseudorapidity Formula Presented. The large-radius jet constituents are further reclustered using the Formula Presented algorithm in order to obtain the splitting parameters, Formula Presented and Formula Presented, which characterize the transverse momentum scale and angular separation for the hardest splitting in the jet, respectively. The nuclear modification factor, Formula Presented, obtained by comparing the Formula Presented jet yields to those in Formula Presented collisions, is measured as a function of jet transverse momentum (Formula Presented) and Formula Presented or Formula Presented. A significant difference in the quenching of large-radius jets having single subjet and those with more complex substructure is observed. Systematic comparison of jet suppression in terms of Formula Presented for different jet definitions is also provided. Presented results support the hypothesis that jets with hard internal splittings lose more energy through quenching and provide a new perspective for understanding the role of jet structure in jet suppression. © 2023 CERN, for the ATLAS Collaboration.Öğe Measurement of the CP properties of Higgs boson interactions with ? -leptons with the ATLAS detector(Institute for Ionics, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliA study of the charge conjugation and parity (CP) properties of the interaction between the Higgs boson and ? -leptons is presented. The study is based on a measurement of CP -sensitive angular observables defined by the visible decay products of ? -leptons produced in Higgs boson decays. The analysis uses 139 fb- 1of proton–proton collision data recorded at a centre-of-mass energy of s=13 TeV with the ATLAS detector at the Large Hadron Collider. Contributions from CP -violating interactions between the Higgs boson and ? -leptons are described by a single mixing angle parameter ??in the generalised Yukawa interaction. Without constraining the H? ?? signal strength to its expected value under the Standard Model hypothesis, the mixing angle ??is measured to be 9?± 16?, with an expected value of 0?± 28?at the 68% confidence level. The pure CP -odd hypothesis is disfavoured at a level of 3.4 standard deviations. The results are compatible with the predictions for the Higgs boson in the Standard Model. © 2023, The Author(s).Öğe Measurement of the cross-sections of the electroweak and total production of a Z? pair in association with two jets in pp collisions at s=13 TeV with the ATLAS detector(Elsevier B.V., 2023) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThis Letter presents the measurement of the fiducial and differential cross-sections of the electroweak production of a Z? pair in association with two jets. The analysis uses 140 fb?1 of LHC proton–proton collision data taken at s=13 TeV recorded by the ATLAS detector during the years 2015–2018. Events with a Z boson candidate decaying into either an e+e? or ?+?? pair, a photon and two jets are selected. The electroweak component is extracted by requiring a large dijet invariant mass and by using the information about the centrality of the system and is measured with an observed and expected significance well above five standard deviations. The fiducial pp?Z?jj cross-section for the electroweak production is measured to be 3.6 ± 0.5 fb. The total fiducial cross-section that also includes contributions where the jets arise from strong interactions is measured to be 16.8?1.8 +2.0 fb. The results are consistent with the Standard Model predictions. Differential cross-sections are also measured using the same events and are compared with parton-shower Monte Carlo simulations. Good agreement is observed between data and predictions. © 2023 The Author(s)Öğe Measurement of the Higgs boson mass with H????? decays in 140 fb?1 of s=13 TeV pp collisions with the ATLAS detector(Elsevier B.V., 2023) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThe mass of the Higgs boson is measured in the H??? decay channel, exploiting the high resolution of the invariant mass of photon pairs reconstructed from the decays of Higgs bosons produced in proton–proton collisions at a centre-of-mass energy s=13 TeV. The dataset was collected between 2015 and 2018 by the ATLAS detector at the Large Hadron Collider, and corresponds to an integrated luminosity of 140 fb?1. The measured value of the Higgs boson mass is 125.17±0.11(stat.)±0.09(syst.) GeV and is based on an improved energy scale calibration for photons, whose impact on the measurement is about four times smaller than in the previous publication. A combination with the corresponding measurement using 7 and 8 TeV pp collision ATLAS data results in a Higgs boson mass measurement of 125.22±0.11(stat.)±0.09(syst.) GeV. With an uncertainty of 1.1 per mille, this is currently the most precise measurement of the mass of the Higgs boson from a single decay channel. © 2023 The Author(s)Öğe Measurement of the production cross-section of J/? and ?(2S) mesons in pp collisions at s=13 TeV with the ATLAS detector(Springer Nature, 2024) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliMeasurements of the differential production cross-sections of prompt and non-prompt J/? and ?(2S) 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/? and ?(2S), and the prompt and non-prompt ?(2S)-to-J/? production ratios, are presented. The analysis is performed using 140 fb-1 of s=13 TeV pp collision data recorded by the ATLAS detector at the LHC during the years 2015–2018. © The Author(s) 2024.Öğe Measurement of the properties of Higgs boson production at ?s = 13 TeV in the H ? ?? channel using 139 fb?1 of pp collision data with the ATLAS experiment(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliMeasurements of Higgs boson production cross-sections are carried out in the diphoton decay channel using 139 fb?1 of pp collision data at s = 13 TeV collected by the ATLAS experiment at the LHC. The analysis is based on the definition of 101 distinct signal regions using machine-learning techniques. The inclusive Higgs boson signal strength in the diphoton channel is measured to be 1.04?0.09+0.10 . Cross-sections for gluon-gluon fusion, vector-boson fusion, associated production with a W or Z boson, and top associated production processes are reported. An upper limit of 10 times the Standard Model prediction is set for the associated production process of a Higgs boson with a single top quark, which has a unique sensitivity to the sign of the top quark Yukawa coupling. Higgs boson production is further characterized through measurements of Simplified Template Cross-Sections (STXS). In total, cross-sections of 28 STXS regions are measured. The measured STXS cross-sections are compatible with their Standard Model predictions, with a p-value of 93%. The measurements are also used to set constraints on Higgs boson coupling strengths, as well as on new interactions beyond the Standard Model in an effective field theory approach. No significant deviations from the Standard Model predictions are observed in these measurements, which provide significant sensitivity improvements compared to the previous ATLAS results. [Figure not available: see fulltext.]. © 2023, The Author(s).Öğe Measurements of differential cross sections of Higgs boson production through gluon fusion in the H? WW*? e??? final state at ?s=13 TeV with the ATLAS detector(Springer Nature, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliHiggs boson production via gluon–gluon fusion is measured in the WW*? e?µ? decay channel. The dataset utilized corresponds to an integrated luminosity of 139 fb - 1 collected by the ATLAS detector from s=13 TeV proton–proton collisions delivered by the Large Hadron Collider between 2015 and 2018. Differential cross sections are measured in a fiducial phase space restricted to the production of at most one additional jet. The results are consistent with Standard Model expectations, derived using different Monte Carlo generators. © 2023, The Author(s).Öğe Model-independent search for the presence of new physics in events including H ? ?? with ?s = 13 TeV pp data recorded by the ATLAS detector at the LHC(Springer Science and Business Media Deutschland GmbH, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.; Çetin, Serkant AliA model-independent search for new physics leading to final states containing a Higgs boson, with a mass of 125.09 GeV, decaying to a pair of photons is performed with 139 fb?1 of s = 13 TeV pp collision data recorded by the ATLAS detector at the Large Hadron Collider at CERN. This search examines 22 final states categorized by the objects that are produced in association with the Higgs boson. These objects include isolated electrons or muons, hadronically decaying ?-leptons, additional photons, missing transverse momentum, and hadronic jets, as well as jets that are tagged as containing a b-hadron. No significant excesses above Standard Model expectations are observed and limits on the production cross section at 95% confidence level are set. Detector efficiencies are reported for all 22 signal regions, which can be used to convert detector-level cross-section limits reported in this paper to particle-level cross-section constraints. [Figure not available: see fulltext.]. © 2023, The Author(s).Öğe Observation of four-top-quark production in the multilepton final state with the ATLAS detector(Springer Nature, 2023) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThis paper presents the observation of four-top-quark (tt¯ tt¯) production in proton-proton collisions at the LHC. The analysis is performed using an integrated luminosity of 140 fb - 1 at a centre-of-mass energy of 13 TeV collected using the ATLAS detector. Events containing two leptons with the same electric charge or at least three leptons (electrons or muons) are selected. Event kinematics are used to separate signal from background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The observed (expected) significance of the measured tt¯ tt¯ signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The tt¯ tt¯ production cross section is measured to be 22.5-5.5+6.6 fb, consistent with the SM prediction of 12.0 ± 2.4 fb within 1.8 standard deviations. Data are also used to set limits on the three-top-quark production cross section, being an irreducible background not measured previously, and to constrain the top-Higgs Yukawa coupling and effective field theory operator coefficients that affect tt¯ tt¯ production. © 2023, The Author(s).Öğe Observation of W?? triboson production in proton-proton collisions at s=13 TeV with the ATLAS detector(Elsevier B.V., 2024) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Çetin, Serkant AliThis letter reports the observation of W(??)?? production in proton-proton collisions. This measurement uses the full Run 2 sample of events recorded at a center-of-mass energy of s=13 TeV by the ATLAS detector at the LHC, corresponding to an integrated luminosity of 140 fb?1. Events with a leptonically-decaying W boson and at least two photons are considered. The background-only hypothesis is rejected with an observed and expected significance of 5.6 standard deviations. The inclusive fiducial production cross section of W(e?)?? and W(??)?? events is measured to be ?fid=13.8±1.1(stat)+2.1?2.0(syst)±0.1(lumi) fb, in agreement with the Standard Model prediction. © 2023 The Author(s)
