magnarkb

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N. J.; Abidi, S. H. & Aboulhorma, A. [Vis alle 2 924 forfattere av denne artikkelen] (2025). Measurements of W+W−production cross-sections in pp collisions at s=13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(8). doi: 10.1007/JHEP08(2025)142. Fulltekst i vitenarkiv Vis sammendrag

  Measurements of W+W− → e±νμ∓ν production cross-sections are presented, providing a test of the predictions of perturbative quantum chromodynamics and the electroweak theory. The measurements are based on data from pp collisions at √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider in 2015–2018, corresponding to an integrated luminosity of 140 fb−1. The number of events due to top-quark pair production, the largest background, is reduced by rejecting events containing jets with b-hadron decays. An improved methodology for estimating the remaining top-quark background enables a precise measurement of W+W− cross-sections with no additional requirements on jets. The fiducial W+W− cross-section is determined in a maximum-likelihood fit with an uncertainty of 3.1%. The measurement is extrapolated to the full phase space, resulting in a total W+W− cross-section of 127 ± 4 pb. Differential cross-sections are measured as a function of twelve observables that comprehensively describe the kinematics of W+W− events. The measurements are compared with state-of-the-art theory calculations and excellent agreement with predictions is observed. A charge asymmetry in the lepton rapidity is observed as a function of the dilepton invariant mass, in agreement with the Standard Model expectation. A CP-odd observable is measured to be consistent with no CP violation. Limits on Standard Model effective field theory Wilson coefficients in the Warsaw basis are obtained from the differential cross-sections.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N. J.; Abidi, S. H. & Aboulhorma, A. [Vis alle 2 925 forfattere av denne artikkelen] (2025). Search for a new scalar decaying into new spin-1 bosons in four-lepton final states with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 865. doi: 10.1016/j.physletb.2025.139472. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 965 forfattere av denne artikkelen] (2025). Expected tracking performance of the ATLAS Inner Tracker at the High-Luminosity LHC. Journal of Instrumentation (JINST). 20(2). doi: 10.1088/1748-0221/20/02/P02018. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 931 forfattere av denne artikkelen] (2024). Study of Z→llγ decays at s = 8 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 84(2). doi: 10.1140/epjc/s10052-024-12471-9. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a study of Z → llγ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20.2 fb−1 collected at a centre-of mass energy √s = 8 TeV. Integrated fiducial cross-sections together with normalised differential fiducial cross-sections, sensitive to the kinematics of final-state QED radiation, are obtained. The results are found to be in agreement with state-of-the-art predictions for final-state QED radiation. First measurements of Z →llγγ decays are also reported.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 880 forfattere av denne artikkelen] (2024). Search for non-resonant production of semi-visible jets using Run 2 data in ATLAS. Physics Letters B. ISSN 0370-2693. 848. doi: 10.1016/j.physletb.2023.138324. Fulltekst i vitenarkiv
• Amerl, M.; Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H. & Ruggeri, T.A. [Vis alle 3 429 forfattere av denne artikkelen] (2024). The ATLAS experiment at the CERN Large Hadron Collider: a description of the detector configuration for Run 3. Journal of Instrumentation (JINST). 19(5). doi: 10.1088/1748-0221/19/05/P05063. Fulltekst i vitenarkiv
• Aad, G.; Aakvaag, Erlend; Abbott, B.; Abbott, D.C.; Abud, Abud Abed & Abeling, K. [Vis alle 2 958 forfattere av denne artikkelen] (2024). Search for pair-produced vectorlike quarks coupling to light quarks in the lepton plus jets final state using 13 TeV pp collisions with the ATLAS detector. Physical Review D. ISSN 2470-0010. 110(5). doi: 10.1103/PhysRevD.110.052009. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 863 forfattere av denne artikkelen] (2024). Probing the CP nature of the top–Higgs Yukawa coupling in tt¯H and tH events with H→bb¯ decays using the ATLAS detector at the LHC. Physics Letters B. ISSN 0370-2693. 849. doi: 10.1016/j.physletb.2024.138469. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 907 forfattere av denne artikkelen] (2024). Search for quantum black hole production in lepton + jet final states using proton-proton collisions at vs = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 109(3). doi: 10.1103/PhysRevD.109.032010. Fulltekst i vitenarkiv Vis sammendrag

  A search for quantum black holes in electron+jet and muon+jet invariant mass spectra is performed with 140  fb−1 of data collected by the ATLAS detector in proton-proton collisions at √𝑠 =13  TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 929 forfattere av denne artikkelen] (2024). Search for leptoquark pair production decaying into te-t¯e+ or tμ-t¯μ+ in multi-lepton final states in pp collisions at s=13TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 84(8). doi: 10.1140/epjc/s10052-024-12975-4. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 929 forfattere av denne artikkelen] (2024). A precise measurement of the Z-boson double-differential transverse momentum and rapidity distributions in the full phase space of the decay leptons with the ATLAS experiment at s=8 TeV. European Physical Journal C. ISSN 1434-6044. 84(3). doi: 10.1140/epjc/s10052-024-12438-w. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 904 forfattere av denne artikkelen] (2024). Measurement of the tt¯ cross section and its ratio to the Z production cross section using pp collisions at s=13.6 TeV with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 848. doi: 10.1016/j.physletb.2023.138376. Fulltekst i vitenarkiv Vis sammendrag

  The inclusive top-quark-pair production cross section 𝜎𝑡̄𝑡 and its ratio to the 𝑍-boson production cross section have been measured in proton–proton collisions at √ 𝑠 = 13.6 TeV, using 29 fb−1 of data collected in 2022 with the ATLAS experiment at the Large Hadron Collider. Using events with an opposite-charge electron-muon pair and 𝑏-tagged jets, and assuming Standard Model decays, the top-quark-pair production cross section is measured to be 𝜎𝑡̄𝑡 = 850 ±3(stat.)±18(syst.)±20(lumi.) pb. The ratio of the 𝑡̄𝑡 and the 𝑍-boson production cross sections is also measured, where the 𝑍-boson contribution is determined for inclusive 𝑒+𝑒− and 𝜇+𝜇− events in a fiducial phase space. The relative uncertainty on the ratio is reduced compared to the 𝑡̄𝑡 cross section, thanks to the cancellation of several systematic uncertainties. The result for the ratio, 𝑅𝑡̄𝑡∕𝑍 = 1.145 ± 0.003(stat.) ± 0.021(syst.) ± 0.002(lumi.) is consistent with the Standard Model prediction using the PDF4LHC21 PDF set.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 919 forfattere av denne artikkelen] (2024). Search for top-philic heavy resonances in pp collisions at s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 84(2). doi: 10.1140/epjc/s10052-023-12318-9. Fulltekst i vitenarkiv Vis sammendrag

  Asearch for the associated production of a heavy resonance with a top-quark or a top-antitop-quark pair, and decaying into a t ¯t pair is presented. The search uses the √data recorded by the ATLAS detector in pp collisions at s = 13 TeV at the Large Hadron Collider during the years 2015–2018, corresponding to an integrated luminosity of 139 fb−1. Events containing exactly one electron ormuon are selected. The two hadronically decaying top quarks from the resonance decay are reconstructed using jets clustered with a large radius parameter of R = 1. The invariant mass spectrum of the two top quark candidates is used to search for a resonance signal in the range of 1.0 TeV to 3.2 TeV. The presence of a signal is examined using an approach with minimal model dependence followed by a model-dependent interpretation. No significant excess is observed over the background expectation. Upper limits on the production cross section times branching ratio at 95% confidence level are provided for a heavy Z' boson based on a simplified model, for Z' mass between 1.0 TeV and 3.0 TeV. The observed (expected) limits range from 21 (14) fb to 119 (86) fb depending on the choice of model parameters.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 908 forfattere av denne artikkelen] (2024). Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at √s = 13 TeV with the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 132(8). doi: 10.1103/PhysRevLett.132.081801. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 907 forfattere av denne artikkelen] (2024). Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 132(13). doi: 10.1103/PhysRevLett.132.131802. Fulltekst i vitenarkiv
• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 890 forfattere av denne artikkelen] (2024). Search for singly produced vectorlike top partners in multilepton final states with 139 fb-1 of pp collision data at s = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 109(11). doi: 10.1103/PhysRevD.109.112012. Fulltekst i vitenarkiv
• Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A.; Sharma, A.S. & White, M.J. [Vis alle 2 843 forfattere av denne artikkelen] (2024). Search for high-mass resonances in final states with a τ-lepton and missing transverse momentum with the ATLAS detector. Physical Review D. ISSN 2470-0010. 109(11). doi: 10.1103/PhysRevD.109.112008. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, A. Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 861 forfattere av denne artikkelen] (2024). Deep Generative Models for Fast Photon Shower Simulation in ATLAS. Computing and Software for Big Science. ISSN 2510-2036. 8(1). doi: 10.1007/s41781-023-00106-9. Fulltekst i vitenarkiv
• Aad, G.; Aakvaag, Erlend; Abbott, B.; Abbott, D.C.; Abud, Abud Abed & Abeling, K. [Vis alle 2 958 forfattere av denne artikkelen] (2024). The ATLAS trigger system for LHC Run 3 and trigger performance in 2022. Journal of Instrumentation (JINST). 19(6). doi: 10.1088/1748-0221/19/06/P06029. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 882 forfattere av denne artikkelen] (2024). Combination and summary of ATLAS dark matter searches interpreted in a 2HDM with a pseudo-scalar mediator using 139 fb⁻¹ of s=13 TeV pp collision data. Science Bulletin. ISSN 2095-9273. 69(19), s. 3005–3035. doi: 10.1016/j.scib.2024.06.003. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 881 forfattere av denne artikkelen] (2024). Test of CP-invariance of the Higgs boson in vector-boson fusion production and in its decay into four leptons. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2024(5). doi: 10.1007/JHEP05(2024)105. Fulltekst i vitenarkiv
• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 890 forfattere av denne artikkelen] (2024). Observation of WZγ Production in pp Collisions at √s=13 TeV with the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 132(2). doi: 10.1103/PhysRevLett.132.021802. Fulltekst i vitenarkiv Vis sammendrag

  This Letter reports the observation of 𝑊⁢𝑍⁢𝛾 production and a measurement of its cross section using 140.1 ±1.2  fb−1 of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The 𝑊⁢𝑍⁢𝛾 production cross section, with both the 𝑊 and 𝑍 bosons decaying leptonically, 𝑝⁢𝑝 →𝑊⁢𝑍⁢𝛾 →ℓ′±⁢𝜈⁢ℓ+⁢ℓ−⁢𝛾 (ℓ(′) =𝑒, 𝜇), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01 ±0.30⁢(stat) ±0.16⁢(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the 𝑊⁢𝑍⁢𝛾 signal is 6.3⁢𝜎, compared with an expected significance of 5.0⁢𝜎.

• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 51 forfattere av denne artikkelen] (2023). Measurement of the production of a 𝑊 boson in association with a charmed hadron in 𝑝⁢𝑝 collisions at √𝑠 =13  TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. doi: 10.1103/PhysRevD.108.032012. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S. H. & Aboulhorma, A. [Vis alle 51 forfattere av denne artikkelen] (2023). Measurement of electroweak Z(νν¯)γjj production and limits on anomalous quartic gauge couplings in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. doi: 10.1007/JHEP06(2023)082. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 885 forfattere av denne artikkelen] (2023). Comparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS. Physics Letters B. ISSN 0370-2693. 846. doi: 10.1016/j.physletb.2023.138154. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 915 forfattere av denne artikkelen] (2023). Measurement of the CP properties of Higgs boson interactions with τ -leptons with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11583-y. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 910 forfattere av denne artikkelen] (2023). Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 131(15), s. 151802–151802. doi: 10.1103/PhysRevLett.131.151802. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 822 forfattere av denne artikkelen] (2023). Search for long-lived, massive particles in events with displaced vertices and multiple jets in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)200. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 921 forfattere av denne artikkelen] (2023). Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings. Physical Review Letters. ISSN 0031-9007. 131(16). doi: 10.1103/PhysRevLett.131.162301. Fulltekst i vitenarkiv Vis sammendrag

  A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the “ridge”—i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities—and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at √s=13  TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8  pb−1, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v2, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 921 forfattere av denne artikkelen] (2023). Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 131(15), s. 151902–151902. doi: 10.1103/PhysRevLett.131.151902. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 821 forfattere av denne artikkelen] (2023). Evidence for the charge asymmetry in pp → tt production at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(8). doi: 10.1007/JHEP08(2023)077. Fulltekst i vitenarkiv
• Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A.; Sharma, A.S. & Ting, E.X.L. [Vis alle 2 868 forfattere av denne artikkelen] (2023). Search for flavor-changing neutral-current couplings between the top quark and the Z boson with proton-proton collisions at √ s = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(3). doi: 10.1103/PhysRevD.108.032019. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 887 forfattere av denne artikkelen] (2023). 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. Physics Letters B. ISSN 0370-2693. 843. doi: 10.1016/j.physletb.2023.137880. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 898 forfattere av denne artikkelen] (2023). Search for resonant WZ production in the fully leptonic final state in proton–proton collisions at √s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11437-7. Fulltekst i vitenarkiv Vis sammendrag

  A search for a WZ resonance, in the fully leptonic final state (electrons or muons), is performed using 139 fb 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.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 955 forfattere av denne artikkelen] (2023). Measurements of the suppression and correlations of dijets in Pb+Pb collisions at^√s<inf>NN</inf> = 5.02 TeV. Physical Review C. ISSN 2469-9985. 107(5). doi: 10.1103/PhysRevC.107.054908. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 810 forfattere av denne artikkelen] (2023). Search for third-generation vector-like leptons in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)118. Fulltekst i vitenarkiv Vis sammendrag

  A search for vector-like leptons in multilepton (two, three, or four-or-more electrons plus muons) final states with zero or more hadronic τ-lepton decays is presented. The search is performed using a dataset corresponding to an integrated luminosity of 139 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. To maximize the separation of signal and background, a machine-learning classifier is used. No excess of events is observed beyond the Standard Model expectation. Using a doublet vector-like lepton model, vector-like leptons coupling to third-generation Standard Model leptons are excluded in the mass range from 130 GeV to 900 GeV at the 95% confidence level, while the highest excluded mass is expected to be 970 GeV.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 829 forfattere av denne artikkelen] (2023). Search for dark photons from Higgs boson decays via ZH production with a photon plus missing transverse momentum signature from pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)133. Fulltekst i vitenarkiv Vis sammendrag

  This paper describes a search for dark photons (γd) in proton-proton collisions at s√ = 13 TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons (H → γγd) produced through the ZH production mode. The transverse mass of the system, made of the photon and the missing transverse momentum from the non-interacting γd, presents a distinctive signature as it peaks near the Higgs boson mass. The results presented use the total Run-2 integrated luminosity of 139 fb−1 recorded by the ATLAS detector at the LHC. The dominant reducible background processes are estimated using data-driven techniques. A Boosted Decision Tree technique is adopted to enhance the sensitivity of the search. As no excess is observed with respect to the Standard Model prediction, an observed (expected) upper limit on the branching ratio BR(H → γγd) of 2.28% (2.82+1.33−0.84%) is set at 95% CL for massless γd. For massive dark photons up to 40 GeV, the observed (expected) upper limits on BR(H → γγd) at 95% confidence level is found within the [2.19,2.52]% ([2.71,3.11]%) range.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 913 forfattere av denne artikkelen] (2023). A search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)200. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 924 forfattere av denne artikkelen] (2023). ATLAS flavour-tagging algorithms for the LHC Run 2 pp collision dataset. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11699-1. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 799 forfattere av denne artikkelen] (2023). Search for dark matter produced in association with a dark Higgs boson decaying into W⁺ W⁻ in the one-lepton final state at √s = 13 TeV using 139 fb⁻¹ of pp collisions recorded with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)116. Fulltekst i vitenarkiv Vis sammendrag

  Several extensions of the Standard Model predict the production of dark matter particles at the LHC. A search for dark matter particles produced in association with a dark Higgs boson decaying into W+W− in the ℓ±νqq¯¯′, final states with ℓ = e, μ is presented. This analysis uses 139 fb−1 of pp collisions recorded by the ATLAS detector at a centre-of-mass energy of 13 TeV. The W± → qq′¯¯¯¯ decays are reconstructed from pairs of calorimeter-measured jets or from track-assisted reclustered jets, a technique aimed at resolving the dense topology from a pair of boosted quarks using jets in the calorimeter and tracking information. The observed data are found to agree with Standard Model predictions. Scenarios with dark Higgs boson masses ranging between 140 and 390 GeV are excluded.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 893 forfattere av denne artikkelen] (2023). Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector. Physical Review Letters. ISSN 0031-9007. 131(18). doi: 10.1103/PhysRevLett.131.181901. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abhayasinghe, D.K. & Abidi, S.H. [Vis alle 2 849 forfattere av denne artikkelen] (2023). Search for pair-production of vector-like quarks in pp collision events at s=13 TeV with at least one leptonically decaying Z boson and a third-generation quark with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 843. doi: 10.1016/j.physletb.2023.138019. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 821 forfattere av denne artikkelen] (2023). Search for a new Z′ gauge boson in 4μ events with the ATLAS experiment. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)090. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a search for a new Z′ vector gauge boson with the ATLAS experiment at the Large Hadron Collider using pp collision data collected at s√ = 13 TeV, corresponding to an integrated luminosity of 139 fb−1. The new gauge boson Z′ is predicted by Lμ − Lτ models to address observed phenomena that can not be explained by the Standard Model. The search examines the four-muon (4μ) final state, using a deep learning neural network classifier to separate the Z′ signal from the Standard Model background events. The di-muon invariant masses in the 4μ events are used to extract the Z′ resonance signature. No significant excess of events is observed over the predicted background. Upper limits at a 95% confidence level on the Z′ production cross-section times the decay branching fraction of pp → Z′μμ → 4μ are set from 0.31 to 4.3 fb for the Z′ mass ranging from 5 to 81 GeV. The corresponding common coupling strengths, gZ′, of the Z′ boson to the second and third generation leptons above 0.003 – 0.2 have been excluded.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 930 forfattere av denne artikkelen] (2023). Observation of four-top-quark production in the multilepton final state with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(6). doi: 10.1140/epjc/s10052-023-11573-0. Fulltekst i vitenarkiv
• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 3 206 forfattere av denne artikkelen] (2023). Measurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector. Physical Review C. ISSN 2469-9985. 107(5). doi: 10.1103/PhysRevC.107.054909. Fulltekst i vitenarkiv Vis sammendrag

  The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon–nucleon center-of-mass energy √sNN=5.02TeV in comparison with proton–proton (pp) collisions at √s=5.02TeV. The Pb+Pb data, collected in 2018, have an integrated luminosity of 1.72nb−1, while the pp data, collected in 2017, have an integrated luminosity of 260pb−1. Jets used in this analysis are clustered using the anti-kt algorithm with a radius parameter R=0.4. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale rg of the first hard splitting inside the jet by reclustering them using the Cambridge–Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, RAA, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in rg, jet transverse momentum, and in intervals of collision centrality. The RAA value is observed to depend significantly on jet rg. Jets produced with the largest measured rg are found to be twice as suppressed as those with the smallest rg in central Pb+Pb collisions. The RAA values do not exhibit a strong variation with jet pT in any of the rg intervals. The rg and pT dependence of jet RAA is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, A. Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 857 forfattere av denne artikkelen] (2023). Searches for new phenomena in events with two leptons, jets, and missing transverse momentum in 139 fb ^{- 1} of √s=13 TeV pp collisions with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(6). doi: 10.1140/epjc/s10052-023-11434-w. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 816 forfattere av denne artikkelen] (2023). Search for an axion-like particle with forward proton scattering in association with photon pairs at ATLAS. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)234. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 788 forfattere av denne artikkelen] (2023). Measurement of the properties of Higgs boson production at √s = 13 TeV in the H → γγ channel using 139 fb⁻¹ of pp collision data with the ATLAS experiment. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)088. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 822 forfattere av denne artikkelen] (2023). Inclusive and differential cross-sections for dilepton tt¯ production measured in √s = 13 TeV pp collisions with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)141. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abidi, S.H. [Vis alle 2 837 forfattere av denne artikkelen] (2023). Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV. Physics Letters B. ISSN 0370-2693. 842. doi: 10.1016/j.physletb.2022.137379. Fulltekst i vitenarkiv
• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 826 forfattere av denne artikkelen] (2023). 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. Physical Review Letters. ISSN 0031-9007. 131(17). doi: 10.1103/PhysRevLett.131.172301. Fulltekst i vitenarkiv
• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 881 forfattere av denne artikkelen] (2023). Integrated and differential fiducial cross-section measurements for the vector boson fusion production of the Higgs boson in the H → WW* → eνμν decay channel at 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(7). doi: 10.1103/PhysRevD.108.072003. Fulltekst i vitenarkiv Vis sammendrag

  The vector-boson production cross section for the Higgs boson decay in the H→WW∗→eνμν channel is measured as a function of kinematic observables sensitive to the Higgs boson production and decay properties as well as integrated in a fiducial phase space. The analysis is performed using the proton-proton collision data collected by the ATLAS detector in Run 2 of the LHC at √s=13  TeV center-of-mass energy, corresponding to an integrated luminosity of 139  fb−1. The different flavor final state is studied by selecting an electron and a muon originating from a pair of W bosons and compatible with the Higgs boson decay. The data are corrected for the effects of detector inefficiency and resolution, and the measurements are compared with different state-of-the-art theoretical predictions. The differential cross sections are used to constrain anomalous interactions described by dimension-six operators in an effective field theory.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 781 forfattere av denne artikkelen] (2023). Search for pair-produced scalar and vector leptoquarks decaying into third-generation quarks and first- or second-generation leptons in pp collisions with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)188. Fulltekst i vitenarkiv Vis sammendrag

  A search for pair-produced scalar and vector leptoquarks decaying into quarks and leptons of different generations is presented. It uses the full LHC Run 2 (2015–2018) data set of 139 fb−1 collected with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of √s = 13 TeV. Scalar leptoquarks with charge −(1/3)e as well as scalar and vector leptoquarks with charge +(2/3)e are considered. All possible decays of the pair-produced leptoquarks into quarks of the third generation (t, b) and charged or neutral leptons of the first or second generation (e, μ, ν) with exactly one electron or muon in the final state are investigated. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section are provided for eight models as a function of the leptoquark mass and the branching ratio of the leptoquark into the charged or neutral lepton. In addition, lower limits on the leptoquark masses are derived for all models across a range of branching ratios. Two of these models have the goal of providing an explanation for the recent B-anomalies. In both models, a vector leptoquark decays into charged and neutral leptons of the second generation with a similar branching fraction. Lower limits of 1980 GeV and 1710 GeV are set on the leptoquark mass for these two models.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 821 forfattere av denne artikkelen] (2023). Measurements of Zγ+jets differential cross sections in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)072. Fulltekst i vitenarkiv Vis sammendrag

  Differential 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.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 777 forfattere av denne artikkelen] (2023). Cross-section measurements for the production of a Z boson in association with high-transverse-momentum jets in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)080. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 933 forfattere av denne artikkelen] (2023). Search for Higgs boson pair production in association with a vector boson in pp collisions at √s=13TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(6). doi: 10.1140/epjc/s10052-023-11559-y. Fulltekst i vitenarkiv Vis sammendrag

  This paper reports a search for Higgs boson pair (hh) production in association with a vector boson (WorZ) using 139 fb−1 of proton–proton collision data at s√=13TeV recorded with the ATLAS detector at the Large Hadron Collider. The search is performed in final states in which the vector boson decays leptonically (W→ℓν,Z→ℓℓ,νν with ℓ=e,μ) and the Higgs bosons each decay into a pair of b-quarks. It targets Vhh signals from both non-resonant hh production, present in the Standard Model (SM), and resonant hh production, as predicted in some SM extensions. A 95% confidence-level upper limit of 183 (87) times the SM cross-section is observed (expected) for non-resonant Vhh production when assuming the kinematics are as expected in the SM. Constraints are also placed on Higgs boson coupling modifiers. For the resonant search, upper limits on the production cross-sections are derived for two specific models: one is the production of a vector boson along with a neutral heavy scalar resonance H, in the mass range 260–1000 GeV, that decays into hh, and the other is the production of a heavier neutral pseudoscalar resonance A that decays into a Z boson and H boson, where the A boson mass is 360–800 GeV and the H boson mass is 260–400 GeV. Constraints are also derived in the parameter space of two-Higgs-doublet models.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 780 forfattere av denne artikkelen] (2023). Search for direct pair production of sleptons and charginos decaying to two leptons and neutralinos with mass splittings near the W-boson mass in √s = 13 TeV pp collisions with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)031. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 892 forfattere av denne artikkelen] (2023). Measurement of the polarisation of W bosons produced in top-quark decays using dilepton events at s=13 TeV with the ATLAS experiment. Physics Letters B. ISSN 0370-2693. 843. doi: 10.1016/j.physletb.2023.137829. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 782 forfattere av denne artikkelen] (2023). Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)019. Fulltekst i vitenarkiv Vis sammendrag

  A 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.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 796 forfattere av denne artikkelen] (2023). Measurement of the tt¯ production cross-section in pp collisions at √s = 5.02 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)138. Fulltekst i vitenarkiv Vis sammendrag

  The inclusive top-quark pair (tt¯) production cross-section σtt¯ is measured in proton–proton collisions at a centre-of-mass energy s√ = 5.02 TeV, using 257 pb−1 of data collected in 2017 by the ATLAS experiment at the LHC. The tt¯ cross-section is measured in both the dilepton and single-lepton final states of the tt¯ system and then combined. The combination of the two measurements yields σtt¯=67.5±0.9(stat.)±2.3(syst.)±1.1(lumi.)±0.2(beam)pb, where the four uncertainties reflect the limited size of the data sample, experimental and theoretical systematic effects, and imperfect knowledge of both the integrated luminosity and the LHC beam energy, giving a total uncertainty of 3.9%. The result is in agreement with theoretical quantum chromodynamic calculations at next-to-next-to-leading order in the strong coupling constant, including the resummation of next-to-next-to-leading logarithmic soft-gluon terms, and constrains the parton distribution functions of the proton at large Bjorken-x.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abreu, H. & Abulaiti, Y. [Vis alle 2 922 forfattere av denne artikkelen] (2023). Measurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(5). doi: 10.1140/epjc/s10052-023-11436-8. Fulltekst i vitenarkiv Vis sammendrag

  In a special run of the LHC with β⋆=2.5 km, proton–proton elastic-scattering events were recorded at s√=13 TeV with an integrated luminosity of 340 μb−1 using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from −t=2.5⋅10−4 GeV2 to −t=0.46 GeV2 using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section σtot, parameters of the nuclear slope, and the ρ-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit t→0. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for σtot and ρ are σtot(pp→X)=104.7±1.1 mb ,ρ=0.098±0.011. The uncertainty in σtot is dominated by the luminosity measurement, and in ρ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 876 forfattere av denne artikkelen] (2023). Measurement of the nuclear modification factor of b-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(5). doi: 10.1140/epjc/s10052-023-11427-9. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a measurement of b-jet production in Pb+Pb and pp collisions at sNN−−−√=5.02 TeV with the ATLAS detector at the LHC. The measurement uses 260 pb−1 of pp collisions collected in 2017 and 1.4 nb−1 of Pb+Pb collisions collected in 2018. In both collision systems, jets are reconstructed via the anti-kt algorithm. The b-jets are identified from a sample of jets containing muons from the semileptonic decay of b-quarks using template fits of the muon momentum relative to the jet axis. In pp collisions, b-jets are reconstructed for radius parameters R=0.2 and R=0.4, and only R=0.2 jets are used in Pb+Pb collisions. For comparison, inclusive R=0.2 jets are also measured using 1.7 nb−1 of Pb+Pb collisions collected in 2018 and the same pp collision data as the b-jet measurement. The nuclear modification factor, RAA, is calculated for both b-jets and inclusive jets with R=0.2 over the transverse momentum range of 80–290 GeV. The nuclear modification factor for b-jets decreases from peripheral to central collisions. The ratio of the b-jet RAA to inclusive jet RAA is also presented and suggests that the RAA for b-jets is larger than that for inclusive jets in central Pb+Pb collisions. The measurements are compared with theoretical calculations and suggest a role for mass and colour-charge effects in partonic energy loss in heavy-ion collisions.

• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 818 forfattere av denne artikkelen] (2023). Search for excited τ-leptons and leptoquarks in the final state with τ-leptons and jets in pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)199. Fulltekst i vitenarkiv Vis sammendrag

  A search is reported for excited τ-leptons and leptoquarks in events with two hadronically decaying τ-leptons and two or more jets. The search uses proton-proton (pp) collision data at s√ = 13 TeV recorded by the ATLAS experiment during the Run 2 of the Large Hadron Collider in 2015–2018. The total integrated luminosity is 139 fb−1. The excited τ-lepton is assumed to be produced and to decay via a four-fermion contact interaction into an ordinary τ-lepton and a quark-antiquark pair. The leptoquarks are assumed to be produced in pairs via the strong interaction, and each leptoquark is assumed to couple to a charm or lighter quark and a τ-lepton. No excess over the background prediction is observed. Excited τ-leptons with masses below 2.8 TeV are excluded at 95% CL in scenarios with the contact interaction scale Λ set to 10 TeV. At the extreme limit of model validity where Λ is set equal to the excited τ-lepton mass, excited τ-leptons with masses below 4.6 TeV are excluded. Leptoquarks with masses below 1.3 TeV are excluded at 95% CL if their branching ratio to a charm quark and a τ-lepton equals 1. The analysis does not exploit flavour-tagging in the signal region.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 912 forfattere av denne artikkelen] (2023). Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(8). doi: 10.1140/epjc/s10052-023-11790-7. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 927 forfattere av denne artikkelen] (2023). Measurement of Zγγ production in pp collisions at √s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(6). doi: 10.1140/epjc/s10052-023-11579-8. Fulltekst i vitenarkiv
• Amerl, M.; Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H. & Ruggeri, T.A. [Vis alle 2 892 forfattere av denne artikkelen] (2023). Anomaly detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using √ s = 13 TeV pp collisions with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(5). doi: 10.1103/PhysRevD.108.052009. Fulltekst i vitenarkiv Vis sammendrag

  A search is presented for a heavy resonance Y decaying into a Standard Model Higgs boson H and a new particle X in a fully hadronic final state. The full Large Hadron Collider run 2 dataset of proton-proton collisions at √s=13  TeV collected by the ATLAS detector from 2015 to 2018 is used and corresponds to an integrated luminosity of 139  fb−1. The search targets the high Y-mass region, where the H and X have a significant Lorentz boost in the laboratory frame. A novel application of anomaly detection is used to define a general signal region, where events are selected solely because of their incompatibility with a learned background-only model. It is constructed using a jet-level tagger for signal-model-independent selection of the boosted X particle, representing the first application of fully unsupervised machine learning to an ATLAS analysis. Two additional signal regions are implemented to target a benchmark X decay into two quarks, covering topologies where the X is reconstructed as either a single large-radius jet or two small-radius jets. The analysis selects Higgs boson decays into b¯b, and a dedicated neural-network-based tagger provides sensitivity to the boosted heavy-flavor topology. No significant excess of data over the expected background is observed, and the results are presented as upper limits on the production cross section σ(pp→Y→XH→q¯qb¯b) for signals with mY between 1.5 and 6 TeV and mX between 65 and 3000 GeV.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 792 forfattere av denne artikkelen] (2023). Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → bb¯ , in proton-proton collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)199. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 902 forfattere av denne artikkelen] (2023). Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb ^{- 1} of proton–proton collisions at √s = 13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11578-9. Fulltekst i vitenarkiv
• Amerl, M.; Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H. & Ruggeri, T.A. [Vis alle 2 891 forfattere av denne artikkelen] (2023). Search in diphoton and dielectron final states for displaced production of Higgs or Z bosons with the ATLAS detector in √ s = 13 TeV pp collisions. Physical Review D. ISSN 2470-0010. 108(1). doi: 10.1103/PhysRevD.108.012012. Fulltekst i vitenarkiv Vis sammendrag

  A search is presented for displaced production of Higgs bosons or Z bosons, originating from the decay of a neutral long-lived particle (LLP) and reconstructed in the decay modes H→γγ and Z→ee. The analysis uses the full Run 2 dataset of proton-proton collisions delivered by the LHC at an energy of √s=13  TeV between 2015 and 2018 and recorded by the ATLAS detector, corresponding to an integrated luminosity of 139  fb−1. Exploiting the capabilities of the ATLAS liquid argon calorimeter to precisely measure the arrival times and trajectories of electromagnetic objects, the analysis searches for the signature of pairs of photons or electrons which arise from a common displaced vertex and which arrive after some delay at the calorimeter. The results are interpreted in a gauge-mediated supersymmetry breaking model with pair-produced Higgsinos that decay to LLPs, and each LLP subsequently decays into either a Higgs boson or a Z boson. The final state includes at least two particles that escape direct detection, giving rise to missing transverse momentum. No significant excess is observed above the background expectation. The results are used to set upper limits on the cross section for Higgsino pair production, up to a ˜χ01 mass of 369 (704) GeV for decays with 100% branching ratio of ˜χ01 to Higgs (Z) bosons for a ˜χ01 lifetime of 2 ns. A model-independent limit is also set on the production of pairs of photons or electrons with a significant delay in arrival at the calorimeter.

• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 835 forfattere av denne artikkelen] (2023). Evidence of off-shell Higgs boson production from ZZ leptonic decay channels and constraints on its total width with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 846. doi: 10.1016/j.physletb.2023.138223. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 785 forfattere av denne artikkelen] (2023). Search for resonant and non-resonant Higgs boson pair production in the bb¯ τ⁺τ⁻ decay channel using 13 TeV pp collision data from the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)040. Fulltekst i vitenarkiv Vis sammendrag

  A search for Higgs boson pair production in events with two b-jets and two τ-leptons is presented, using a proton–proton collision dataset with an integrated luminosity of 139 fb−1 collected at s√ = 13 TeV by the ATLAS experiment at the LHC. Higgs boson pairs produced non-resonantly or in the decay of a narrow scalar resonance in the mass range from 251 to 1600 GeV are targeted. Events in which at least one τ-lepton decays hadronically are considered, and multivariate discriminants are used to reject the backgrounds. No significant excess of events above the expected background is observed in the non-resonant search. The largest excess in the resonant search is observed at a resonance mass of 1 TeV, with a local (global) significance of 3.1σ (2.0σ). Observed (expected) 95% confidence-level upper limits are set on the non-resonant Higgs boson pair-production cross-section at 4.7 (3.9) times the Standard Model prediction, assuming Standard Model kinematics, and on the resonant Higgs boson pair-production cross-section at between 21 and 900 fb (12 and 840 fb), depending on the mass of the narrow scalar resonance.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 739 forfattere av denne artikkelen] (2023). Search for heavy, long-lived, charged particles with large ionisation energy loss in pp collisions at √s = 13 TeV using the ATLAS experiment and the full Run 2 dataset. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(6). doi: 10.1007/JHEP06(2023)158. Fulltekst i vitenarkiv Vis sammendrag

  This 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.

• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 837 forfattere av denne artikkelen] (2023). Measurements of Higgs boson production by gluon-gluon fusion and vector-boson fusion using H→WW*→eνμν decays in pp collisions at √ s = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(3). doi: 10.1103/PhysRevD.108.032005. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 782 forfattere av denne artikkelen] (2023). Search for tt¯ H/ A→ tt¯ tt¯ production in the multilepton final state in proton–proton collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)203. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 929 forfattere av denne artikkelen] (2023). Calibration of the light-flavour jet mistagging efficiency of the b-tagging algorithms with Z+jets events using 139 fb ^{- 1} of ATLAS proton–proton collision data at √s=13 TeV. European Physical Journal C. ISSN 1434-6044. 83(8). doi: 10.1140/epjc/s10052-023-11736-z. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 936 forfattere av denne artikkelen] (2023). Measurements of observables sensitive to colour reconnection in tt¯ events with the ATLAS detector at √s= 13 TeV. European Physical Journal C. ISSN 1434-6044. 83(6). doi: 10.1140/epjc/s10052-023-11479-x. Fulltekst i vitenarkiv Vis sammendrag

  A measurement of observables sensitive to effects of colour reconnection in top-quark pair-production events is presented using 139 of 13 TeV proton–proton collision data collected by the ATLAS detector at the LHC. Events are selected by requiring exactly one isolated electron and one isolated muon with opposite charge and two or three jets, where exactly two jets are required to be b-tagged. For the selected events, measurements are presented for the charged-particle multiplicity, the scalar sum of the transverse momenta of the charged particles, and the same scalar sum in bins of charged-particle multiplicity. These observables are unfolded to the stable-particle level, thereby correcting for migration effects due to finite detector resolution, acceptance and efficiency effects. The particle-level measurements are compared with different colour reconnection models in Monte Carlo generators. These measurements disfavour some of the colour reconnection models and provide inputs to future optimisation of the parameters in Monte Carlo generators.

• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 874 forfattere av denne artikkelen] (2023). Luminosity determination in pp collisions at √s=13 TeV using the ATLAS detector at the LHC. European Physical Journal C. ISSN 1434-6044. 83(10). doi: 10.1140/epjc/s10052-023-11747-w. Fulltekst i vitenarkiv
• Amerl, M.; Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H. & Ruggeri, T.A. [Vis alle 2 848 forfattere av denne artikkelen] (2023). Search for nonresonant pair production of Higgs bosons in the bb¯bb¯ final state in pp collisions at √ s = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(5). doi: 10.1103/PhysRevD.108.052003. Fulltekst i vitenarkiv Vis sammendrag

  A search for nonresonant Higgs boson pair production in the b¯bb¯b final state is presented. The analysis uses 126  fb−1 of pp collision data at √s=13  TeV collected with the ATLAS detector at the Large Hadron Collider, and targets both the gluon-gluon fusion and vector-boson fusion production modes. No evidence of the signal is found and the observed (expected) upper limit on the cross section for nonresonant Higgs boson pair production is determined to be 5.4 (8.1) times the Standard Model predicted cross section at 95% confidence level. Constraints are placed on modifiers to the HHH and HHVV couplings. The observed (expected) 2σ constraints on the HHH coupling modifier, κλ, are determined to be [−3.5,11.3] ([−5.4,11.4]), while the corresponding constraints for the HHVV coupling modifier, κ2V, are [−0.0,2.1] ([−0.1,2.1]). In addition, constraints on relevant coefficients are derived in the context of the Standard Model effective field theory and Higgs effective field theory, and upper limits on the HH production cross section are placed in seven Higgs effective field theory benchmark scenarios.

• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 878 forfattere av denne artikkelen] (2023). Search for pair production of third-generation leptoquarks decaying into a bottom quark and a τ -lepton with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(11). doi: 10.1140/epjc/s10052-023-12104-7. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 881 forfattere av denne artikkelen] (2023). Measurements of differential cross sections of Higgs boson production through gluon fusion in the H? WW^*? e?µ? final state at √s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(9). doi: 10.1140/epjc/s10052-023-11873-5. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 916 forfattere av denne artikkelen] (2023). Search for supersymmetry in final states with missing transverse momentum and three or more b-jets in 139 fb^-1 of proton–proton collisions at √s=13 TeV with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11543-6. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 771 forfattere av denne artikkelen] (2023). Model-independent search for the presence of new physics in events including H → γγ with √s = 13 TeV pp data recorded by the ATLAS detector at the LHC. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)176. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 898 forfattere av denne artikkelen] (2023). Search for dark matter produced in association with a single top quark and an energetic W boson in √s= 13 TeV pp collisions with the ATLAS detector. European Physical Journal C. ISSN 1434-6044. 83(7). doi: 10.1140/epjc/s10052-023-11582-z. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 893 forfattere av denne artikkelen] (2023). Correlations between flow and transverse momentum in Xe + Xe and Pb + Pb collisions at the LHC with the ATLAS detector: A probe of the heavy-ion initial state and nuclear deformation. Physical Review C. ISSN 2469-9985. 107(5). doi: 10.1103/PhysRevC.107.054910. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abdinov, O.; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 922 forfattere av denne artikkelen] (2023). Measurement of muon pairs produced via γγ scattering in nonultraperipheral Pb + Pb collisions at √sNN = 5.02 TeV with the ATLAS detector. Physical Review C. ISSN 2469-9985. 107(5). doi: 10.1103/PhysRevC.107.054907. Fulltekst i vitenarkiv Vis sammendrag

  Results of a measurement of dimuon photoproduction in nonultraperipheral Pb+Pb collisions at √sNN=5.02 TeV are presented. The measurement uses ATLAS data from the 2015 and 2018 Pb+Pb data-taking periods at the LHC with an integrated luminosity of 1.94nb−1. The γγ→μ+μ− pairs are identified via selections on pair momentum asymmetry and acoplanarity. Differential cross sections for dimuon production are measured in different centrality, average muon momentum, and pair rapidity intervals as functions of acoplanarity and k⊥, the transverse momentum kick of one muon relative to the other. Measurements are also made as a function of the rapidity separation of the muons and the angle of the muon pair relative to the second-order event plane to test whether magnetic fields generated in the quark-gluon plasma affect the measured muons. A prior observation of a centrality-dependent broadening of the acoplanarity distribution is confirmed. Furthermore, the improved precision of the measurement reveals a depletion in the number of pairs having small acoplanarity or k⊥ values in more central collisions. The acoplanarity distributions in a given centrality interval are observed to vary with the mean pT of the muons in the pair, but the k⊥ distributions do not. Comparisons with recent theoretical predictions are made. The predicted trends associated with effects of magnetic fields on the dimuons are not observed.

• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 869 forfattere av denne artikkelen] (2023). Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS. Physical Review Letters. ISSN 0031-9007. 131(7). doi: 10.1103/PhysRevLett.131.072301. Fulltekst i vitenarkiv Vis sammendrag

  Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36  nb−1 of p+Pb and 3.6  pb−1 of pp collisions at 5.02 TeV. The yields of charged hadrons with pchT>0.5  GeV near and opposite in azimuth to jets with pjetT>30 or 60 GeV, and the ratios of these yields between p+Pb and pp collisions, IpPb, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The IpPb values are consistent with unity within a few percent for hadrons with pchT>4  GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.

• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 857 forfattere av denne artikkelen] (2023). Measurements of the suppression and correlations of dijets in Xe+Xe collisions at √sNN = 5.44 TeV. Physical Review C. ISSN 2469-9985. 108(2). doi: 10.1103/PhysRevC.108.024906. Fulltekst i vitenarkiv Vis sammendrag

  Measurements of the suppression and correlations of dijets is performed using 3µb−1 of Xe+Xe data at √sNN=5.44 TeV collected with the ATLAS detector at the CERN Large Hadron Collider. Dijets with jets reconstructed using the R=0.4 anti-kt algorithm are measured differentially in jet pT over the range of 32 to 398 GeV and the centrality of the collisions. Significant dijet momentum imbalance is found in the most central Xe+Xe collisions, which decreases in more peripheral collisions. Results from the measurement of per-pair normalized and absolutely normalized dijet pT balance are compared with previous Pb+Pb measurements at √sNN=5.02 TeV. The differences between the dijet suppression in Xe+Xe and Pb+Pb are further quantified by the ratio of pair nuclear-modification factors. The results are found to be consistent with those measured in Pb+Pb data when compared in classes of the same event activity and when taking into account the difference between the center-of-mass energies of the initial parton scattering process in Xe+Xe and Pb+Pb collisions. These results should provide input for a better understanding of the role of energy density, system size, path length, and fluctuations in the parton energy loss.

• Filmer, E.K.; Jackson, P.; Kong, A.X.Y.; Potti, H.; Ruggeri, T.A. & Ting, E.X.L. [Vis alle 2 855 forfattere av denne artikkelen] (2023). Measurement of the production of a W boson in association with a charmed hadron in pp collisions at √s = 13 TeV with the ATLAS detector. Physical Review D. ISSN 2470-0010. 108(3). doi: 10.1103/PhysRevD.108.032012. Fulltekst i vitenarkiv
• Jackson, P.; Oliver, J.L.; Petridis, A.; Qureshi, A.; Sharma, A.S. & White, M.J. [Vis alle 2 861 forfattere av denne artikkelen] (2023). Measurement of the inclusive tt¯ production cross section in the lepton+jets channel in pp collisions at √ s = 7 TeV with the ATLAS detector using support vector machines. Physical Review D. ISSN 2470-0010. 108(3). doi: 10.1103/PhysRevD.108.032014. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 839 forfattere av denne artikkelen] (2023). Search for exclusive Higgs and Z boson decays to ωγ and Higgs boson decays to K^⁎γ with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 847. doi: 10.1016/j.physletb.2023.138292. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 891 forfattere av denne artikkelen] (2023). Search for pairs of muons with small displacements in pp collisions at s=13 TeV with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 846. doi: 10.1016/j.physletb.2023.138172. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 875 forfattere av denne artikkelen] (2023). Search for heavy long-lived multi-charged particles in the full LHC Run 2 pp collision data at s=13 TeV using the ATLAS detector. Physics Letters B. ISSN 0370-2693. 847. doi: 10.1016/j.physletb.2023.138316. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abud, Abud Abed; Abeling, K. & Abhayasinghe, D.K. [Vis alle 2 788 forfattere av denne artikkelen] (2023). Search for high-mass Wγ and Zγ resonances using hadronic W/Z boson decays from 139 fb⁻¹ of pp collisions at √s = 13 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)125. Fulltekst i vitenarkiv Vis sammendrag

  A search for high-mass charged and neutral bosons decaying to Wγ and Zγ final states is presented in this paper. The analysis uses a data sample of s√ = 13 TeV proton-proton collisions with an integrated luminosity of 139 fb−1 collected by the ATLAS detector during LHC Run 2 operation. The sensitivity of the search is determined using models of the production and decay of spin-1 charged bosons and spin-0/2 neutral bosons. The range of resonance masses explored extends from 1.0 TeV to 6.8 TeV. At these high resonance masses, it is beneficial to target the hadronic decays of the W and Z bosons because of their large branching fractions. The decay products of the high-momentum W/Z bosons are strongly collimated and boosted-boson tagging techniques are employed to improve the sensitivity. No evidence of a signal above the Standard Model backgrounds is observed, and upper limits on the production cross-sections of these bosons times their branching fractions to Wγ and Zγ are derived for various boson production models.

• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 888 forfattere av denne artikkelen] (2023). Observation of gauge boson joint-polarisation states in W^±Z production from pp collisions at s=13 TeV with the ATLAS detector. Physics Letters B. ISSN 0370-2693. 843. doi: 10.1016/j.physletb.2023.137895. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 791 forfattere av denne artikkelen] (2023). Search for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb−1 of 13 TeV pp collisions with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)155. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 770 forfattere av denne artikkelen] (2023). Charged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at √sNN = 5 TeV with the ATLAS detector at the LHC. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2023(7). doi: 10.1007/JHEP07(2023)074. Fulltekst i vitenarkiv Vis sammendrag

  This 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 μb−1, respectively. The nuclear modification factors RpPb and RAA 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 pT ≈ 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 pT-dependence with a local maximum at pT ≈ 2 GeV and a local minimum at pT ≈ 7 GeV. This dependence is more distinguishable in more central collisions. No significant |η|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe RAA better in central collisions and in the pT range from about 10 to 100 GeV.

• Jackson, P.; Kong, A.X.Y.; Oliver, J.L.; Ruggeri, T.A.; Sharma, A.S. & White, M.J. [Vis alle 2 884 forfattere av denne artikkelen] (2023). Measurement of cross sections for production of a Z boson in association with a flavor-inclusive or doubly b-tagged large-radius jet in proton-proton collisions at √ s = 13 with the ATLAS experiment. Physical Review D. ISSN 2470-0010. 108(1). doi: 10.1103/PhysRevD.108.012022. Fulltekst i vitenarkiv Vis sammendrag

  We present measurements of cross sections for production of a leptonically decaying Z boson in association with a large-radius jet in 13 TeV proton-proton collisions at the LHC, using 36  fb−1 of data from the ATLAS detector. Integrated and differential cross sections are measured at particle level in both a flavor inclusive and a doubly b-tagged fiducial phase space. The large-radius jet mass and transverse momentum, its kinematic relationship to the Z boson, and the angular separation of b-tagged small-radius track jets within the large-radius jet are measured. This measurement constitutes an important test of perturbative quantum chromodynamics in kinematic and flavor configurations relevant to several Higgs boson and beyond-Standard-Model physics analyses. The results highlight issues with modeling of additional hadronic activity in the flavor-inclusive selection, and a distinction between flavor-number schemes in the b-tagged phase space.

• Aad, G.; Abbott, B.; Abeling, K.; Abidi, S.H.; Aboulhorma, A. & Abramowicz, H. [Vis alle 2 834 forfattere av denne artikkelen] (2023). 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. Physics Letters B. ISSN 0370-2693. 842. doi: 10.1016/j.physletb.2023.137963. Fulltekst i vitenarkiv
• Aad, G.; Abbott, B.; Abbott, D.C.; Abeling, K.; Abidi, S.H. & Aboulhorma, A. [Vis alle 2 889 forfattere av denne artikkelen] (2023). Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment. Physics Letters B. ISSN 0370-2693. 843. doi: 10.1016/j.physletb.2023.137848. Fulltekst i vitenarkiv

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• Aad, G.; Abbott, B.; Abbott, D. C.; Abeling, K.; Abidi, S. H. & Aboulhorma, A. [Vis alle 2 906 forfattere av denne artikkelen] (2025). Erratum: Search for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb−1 of 13 TeV pp collisions with the ATLAS detector. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(12). doi: 10.1007/JHEP12(2025)143. Fulltekst i vitenarkiv

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