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Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (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, 84(3), Article ID 315.
Open this publication in new window or tab >>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
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2024 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 84, no 3, article id 315Article in journal (Refereed) Published
Abstract [en]

This paper presents for the first time a precise measurement of the production properties of the Z boson in the full phase space of the decay leptons. This is in contrast to the many previous precise unfolded measurements performed in the fiducial phase space of the decay leptons. The measurement is obtained from proton–proton collision data collected by the ATLAS experiment in 2012 at s=8 TeV at the LHC and corresponding to an integrated luminosity of 20.2 fb-1. The results, based on a total of 15.3 million Z-boson decays to electron and muon pairs, extend and improve a previous measurement of the full set of angular coefficients describing Z-boson decay. The double-differential cross-section distributions in Z-boson transverse momentum pT and rapidity y are measured in the pole region, defined as 80<mℓℓ<100 GeV, over the range |y|<3.6. The total uncertainty of the normalised cross-section measurements in the peak region of the pT distribution is dominated by statistical uncertainties over the full range and increases as a function of rapidity from 0.5–1.0% for |y|<2.0 to 2-7% at higher rapidities. The results for the rapidity-dependent transverse momentum distributions are compared to state-of-the-art QCD predictions, which combine in the best cases approximate N4LL resummation with N3LO fixed-order perturbative calculations. The differential rapidity distributions integrated over pT are even more precise, with accuracies from 0.2–0.3% for |y|<2.0 to 0.4–0.9% at higher rapidities, and are compared to fixed-order QCD predictions using the most recent parton distribution functions. The agreement between data and predictions is quite good in most cases.

Place, publisher, year, edition, pages
Springer Nature, 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-346172 (URN)10.1140/epjc/s10052-024-12438-w (DOI)2-s2.0-85190755857 (Scopus ID)
Note

QC 20240506

Available from: 2024-05-03 Created: 2024-05-03 Last updated: 2024-05-06Bibliographically approved
Hayrapetyan, A., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Combination of Measurements of the Top Quark Mass from Data Collected by the ATLAS and CMS Experiments at Formula Presented and 8 TeV. Physical Review Letters, 132(26), Article ID 261902.
Open this publication in new window or tab >>Combination of Measurements of the Top Quark Mass from Data Collected by the ATLAS and CMS Experiments at Formula Presented and 8 TeV
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2024 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 132, no 26, article id 261902Article in journal (Refereed) Published
Abstract [en]

A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The datasets used correspond to an integrated luminosity of up to 5 and Formula Presented of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak Formula Presented channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is Formula Presented, with a total uncertainty of 0.33 GeV.

Place, publisher, year, edition, pages
American Physical Society (APS), 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-350693 (URN)10.1103/PhysRevLett.132.261902 (DOI)2-s2.0-85197696145 (Scopus ID)
Note

QC 20240719

Available from: 2024-07-17 Created: 2024-07-17 Last updated: 2024-07-19Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Combination of searches for pair-produced leptoquarks at s=13 TeV with the ATLAS detector. Physics Letters B, 854, Article ID 138736.
Open this publication in new window or tab >>Combination of searches for pair-produced leptoquarks at s=13 TeV with the ATLAS detector
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2024 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 854, article id 138736Article in journal (Refereed) Published
Abstract [en]

A statistical combination of various searches for pair-produced leptoquarks is presented, using the full LHC Run 2 (2015–2018) data set of 139 fb−1 collected with the ATLAS detector from proton–proton collisions at a centre-of-mass energy of s=13 TeV. All possible decays of the leptoquarks into quarks of the third generation and charged or neutral leptons of any generation are investigated. Since no significant deviations from the Standard Model expectation are observed in any of the individual analyses, combined exclusion limits are set on the production cross-sections for scalar and vector leptoquarks. The resulting lower bounds on leptoquark masses exceed those from the individual analyses by up to 100 GeV, depending on the signal hypothesis.

Place, publisher, year, edition, pages
Elsevier BV, 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-347286 (URN)10.1016/j.physletb.2024.138736 (DOI)2-s2.0-85194415100 (Scopus ID)
Note

QC 20240610

Available from: 2024-06-10 Created: 2024-06-10 Last updated: 2024-06-10Bibliographically approved
Filmer, E. K., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Combination of Searches for Resonant Higgs Boson Pair Production Using Formula Presented Collisions at Formula Presented with the ATLAS Detector. Physical Review Letters, 132(23), Article ID 231801.
Open this publication in new window or tab >>Combination of Searches for Resonant Higgs Boson Pair Production Using Formula Presented Collisions at Formula Presented with the ATLAS Detector
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2024 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 132, no 23, article id 231801Article in journal (Refereed) Published
Abstract [en]

A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to Formula Presented of Formula Presented collision data at Formula Presented recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: Formula Presented, Formula Presented, and Formula Presented. No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV-5 TeV. The observed (expected) limits are in the range 0.96-600 fb (1.2-390 fb). The limits are interpreted in the type-I two-Higgs-doublet model and the minimal supersymmetric standard model, and constrain parameter space not previously excluded by other searches.

Place, publisher, year, edition, pages
American Physical Society (APS), 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-348761 (URN)10.1103/PhysRevLett.132.231801 (DOI)38905640 (PubMedID)2-s2.0-85196005989 (Scopus ID)
Note

QC 20240627

Available from: 2024-06-27 Created: 2024-06-27 Last updated: 2024-07-03Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . Zwalinski, L. (2024). Differential cross-section measurements of the production of four charged leptons in association with two jets using the ATLAS detector. Journal of High Energy Physics (JHEP), 2024(1), Article ID 4.
Open this publication in new window or tab >>Differential cross-section measurements of the production of four charged leptons in association with two jets using the ATLAS detector
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2024 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2024, no 1, article id 4Article in journal (Refereed) Published
Abstract [en]

Differential cross-sections are measured for the production of four charged leptons in association with two jets. These measurements are sensitive to final states in which the jets are produced via the strong interaction as well as to the purely-electroweak vector boson scattering process. The analysis is performed using proton-proton collision data collected by ATLAS at root s = 13TeV and with an integrated luminosity of 140 fb(-1). The data are corrected for the effects of detector inefficiency and resolution and are compared to stateof-the-art Monte Carlo event generator predictions. The differential cross-sections are used to search for anomalous weak-boson self-interactions that are induced by dimension-six and dimension-eight operators in Standard Model effective field theory.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Hadron-Hadron Scattering
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-345134 (URN)10.1007/JHEP01(2024)004 (DOI)001184438800001 ()
Note

QC 20240408

Available from: 2024-04-08 Created: 2024-04-08 Last updated: 2024-04-08Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . Zhokin, A. (2024). Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC. Physical Review Letters, 132(2), Article ID 021803.
Open this publication in new window or tab >>Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC
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2024 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 132, no 2, article id 021803Article in journal (Refereed) Published
Abstract [en]

The first evidence for the Higgs boson decay to a Z 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 140 fb-1 for each experiment, at a center -of -mass energy of 13 TeV. The measured signal yield is 2.2 +/- 0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.

Place, publisher, year, edition, pages
American Physical Society (APS), 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-346098 (URN)10.1103/PhysRevLett.132.021803 (DOI)001185794500011 ()38277607 (PubMedID)2-s2.0-85182246849 (Scopus ID)
Note

QC 20240503

Available from: 2024-05-03 Created: 2024-05-03 Last updated: 2024-05-03Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Measurement of t-channel single-top-quark production in pp collisions at s=5.02 TeV with the ATLAS detector. Physics Letters B, 854, Article ID 138726.
Open this publication in new window or tab >>Measurement of t-channel single-top-quark production in pp collisions at s=5.02 TeV with the ATLAS detector
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2024 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 854, article id 138726Article in journal (Refereed) Published
Abstract [en]

The observation of the electroweak production of single-top-quarks is made using 255 pb−1 of proton-proton collision data recorded at s=5.02 TeV with the ATLAS detector at the Large Hadron Collider. An event selection is used to identify single-top-quark candidates arising from t-channel production with the top quark decaying semi-leptonically. Events passing the selection are then used to measure the inclusive cross-section for the combined production of single-top-quarks and antiquarks, σ(tq+t¯q), and the ratio Rt between these two. They are measured to be σ(tq+t¯q)=27.1−4.1+4.4(stat.)−3.7+4.4(syst.) pb and Rt=2.73−0.82+1.43(stat.)−0.29+1.01(syst.). The individual single-top-quark (tq) and single-top-antiquark (t¯q) production cross-sections are measured to be σ(tq)=19.8−3.1+3.9(stat.)−2.2+2.9(syst.) pb and σ(t¯q)=7.3−2.1+3.2(stat.)−1.5+2.8(syst.) pb. All measurements are in good agreement with the Standard Model predictions.

Place, publisher, year, edition, pages
Elsevier B.V., 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-347302 (URN)10.1016/j.physletb.2024.138726 (DOI)2-s2.0-85194176733 (Scopus ID)
Note

QC 20240610

Available from: 2024-06-10 Created: 2024-06-10 Last updated: 2024-06-10Bibliographically approved
Filmer, E. K., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Measurement of the Centrality Dependence of the Dijet Yield in Formula Presented Collisions at Formula Presented with the ATLAS Detector. Physical Review Letters, 132(10), Article ID 102301.
Open this publication in new window or tab >>Measurement of the Centrality Dependence of the Dijet Yield in Formula Presented Collisions at Formula Presented with the ATLAS Detector
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2024 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 132, no 10, article id 102301Article in journal (Refereed) Published
Abstract [en]

ATLAS measured the centrality dependence of the dijet yield using Formula Presented of Formula Presented data collected at Formula Presented in 2016. The event centrality, which reflects the Formula Presented impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter. The central-to-peripheral ratio of the scaled dijet yields, Formula Presented, is evaluated, and the results are presented as a function of variables that reflect the kinematics of the initial hard parton scattering process. The Formula Presented shows a scaling with the Bjorken Formula Presented of the parton originating from the proton, Formula Presented, while no such trend is observed as a function of Formula Presented. This analysis provides unique input to understanding the role of small proton spatial configurations in Formula Presented collisions by covering parton momentum fractions from the valence region down to Formula Presented and Formula Presented.

Place, publisher, year, edition, pages
American Physical Society (APS), 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-344595 (URN)10.1103/PhysRevLett.132.102301 (DOI)001202029400003 ()38518341 (PubMedID)2-s2.0-85193551944 (Scopus ID)
Note

QC 20240503

Available from: 2024-03-20 Created: 2024-03-20 Last updated: 2024-06-03Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Measurement of the H→ γγ and H→ ZZ<sup>∗</sup>→ 4 ℓ cross-sections in pp collisions at √s=13.6 TeV with the ATLAS detector. European Physical Journal C, 84(1), Article ID 78.
Open this publication in new window or tab >>Measurement of the H→ γγ and H→ ZZ<sup>∗</sup>→ 4 ℓ cross-sections in pp collisions at √s=13.6 TeV with the ATLAS detector
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2024 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 84, no 1, article id 78Article in journal (Refereed) Published
Abstract [en]

The inclusive Higgs boson production cross-section is measured in the di-photon and the ZZ∗→ 4 ℓ decay channels using 31.4 and 29.0 fb - 1 of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of s=13.6 TeV . To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σfid,γγ= 76-13+14 fb, and σfid,4ℓ= 2.80±0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6 ± 3.7 fb and 3.67 ± 0.19 fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ(pp→H)=67-11+12 pb and 46 ± 12 pb at 13.6 TeV from the di-photon and ZZ∗→ 4 ℓ measurements respectively. The two measurements are combined into a total cross-section measurement of σ(pp→ H) = 58.2 ± 8.7 pb, to be compared with the Standard Model prediction of σ(pp→ H) SM= 59.9 ± 2.6 pb.

Place, publisher, year, edition, pages
Institute for Ionics, 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-342828 (URN)10.1140/epjc/s10052-023-12130-5 (DOI)001161543700001 ()2-s2.0-85183047904 (Scopus ID)
Note

QC 20240402

Available from: 2024-01-31 Created: 2024-01-31 Last updated: 2024-04-02Bibliographically approved
Aad, G., Leopold, A., Lundberg, O., Lund-Jensen, B., Ohm, C., Shaheen, R., . . . et al., . (2024). Measurement of the production cross-section of J/ψ and ψ(2S) mesons in pp collisions at s=13 TeV with the ATLAS detector. European Physical Journal C, 84(2), Article ID 169.
Open this publication in new window or tab >>Measurement of the production cross-section of J/ψ and ψ(2S) mesons in pp collisions at s=13 TeV with the ATLAS detector
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2024 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 84, no 2, article id 169Article in journal (Refereed) Published
Abstract [en]

Measurements of the differential production cross-sections of prompt and non-prompt J/ψ and ψ(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/ψ and ψ(2S), and the prompt and non-prompt ψ(2S)-to-J/ψ 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.

Place, publisher, year, edition, pages
Springer Nature, 2024
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-344576 (URN)10.1140/epjc/s10052-024-12439-9 (DOI)001185540100001 ()2-s2.0-85186903501 (Scopus ID)
Note

QC 20240321

Available from: 2024-03-20 Created: 2024-03-20 Last updated: 2024-05-03Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-8015-7512

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