| 781. |
- Milstead, David A., et al.
(författare)
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Search for photonic signatures of gauge-mediated supersymmetry in 13 TeV pp collisions with the ATLAS detector
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:9
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Tidskriftsartikel (refereegranskat)abstract
- Searches for dijet resonances with sub-TeV masses using the ATLAS detector at the Large Hadron Collider can be statistically limited by the bandwidth available to inclusive single-jet triggers, whose data-collection rates at low transverse momentum are much lower than the rate from standard model multijet production. This Letter describes a new search for dijet resonances where this limitation is overcome by recording only the event information calculated by the jet trigger algorithms, thereby allowing much higher event rates with reduced storage needs. The search targets low-mass dijet resonances in the range 450-1800 GeV. The analyzed data set has an integrated luminosity of up to 29.3 fb-1 and was recorded at a center-of-mass energy of 13 TeV. No excesses are found; limits are set on Gaussian-shaped contributions to the dijet mass distribution from new particles and on a model of dark-matter particles with axial-vector couplings to quarks. © 2018 CERN, for the ATLAS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 .
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| 782. |
- Milstead, David A., et al.
(författare)
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Search for scalar leptoquarks in pp collisions at √S = 13TeV with the ATLAS experiment
- 2016
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 18:9, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- An inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in pp collisions at s √S13 TeV at the large hadron collider, have been considered. An integrated luminosity of 3.2 fb−1, corresponding to the full 2015 dataset was used. First (second) generation leptoquarks were sought in events with two electrons (muons) and two or more jets. The observed event yield in each channel is consistent with Standard Model background expectations. The observed (expected) lower limits on the leptoquark mass at 95% confidence level are 1100 and 1050 GeV (1160 and 1040 GeV) for first and second generation leptoquarks, respectively, assuming a branching ratio into a charged lepton and a quark of 100%. Upper limits on the aforementioned branching ratio are also given as a function of leptoquark mass. Compared with the results of earlier ATLAS searches, the sensitivity is increased for leptoquark masses above 860 GeV, and the observed exclusion limits confirm and extend the published results. © 2016 CERN for the benefit of the ATLAS Collaboration.
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| 783. |
- Milstead, David A., et al.
(författare)
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Search for squarks and gluinos in final states with jets and missing transverse momentum using 36 fb-1 of √s =13 TeV pp collision data with the ATLAS detector
- 2018
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:11
-
Tidskriftsartikel (refereegranskat)abstract
- Searches for dijet resonances with sub-TeV masses using the ATLAS detector at the Large Hadron Collider can be statistically limited by the bandwidth available to inclusive single-jet triggers, whose data-collection rates at low transverse momentum are much lower than the rate from standard model multijet production. This Letter describes a new search for dijet resonances where this limitation is overcome by recording only the event information calculated by the jet trigger algorithms, thereby allowing much higher event rates with reduced storage needs. The search targets low-mass dijet resonances in the range 450-1800 GeV. The analyzed data set has an integrated luminosity of up to 29.3 fb-1 and was recorded at a center-of-mass energy of 13 TeV. No excesses are found; limits are set on Gaussian-shaped contributions to the dijet mass distribution from new particles and on a model of dark-matter particles with axial-vector couplings to quarks. © 2018 CERN, for the ATLAS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 .
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| 784. |
- Milstead, David A., et al.
(författare)
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Search for the Decay of the Higgs Boson to Charm Quarks with the ATLAS Experiment
- 2018
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 1079-7114 .- 0031-9007. ; 120:21
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Tidskriftsartikel (refereegranskat)abstract
- A direct search for the standard model Higgs boson decaying to a pair of charm quarks is presented. Associated production of the Higgs and Z bosons, in the decay mode ZH→ + -cc is studied. A data set with an integrated luminosity of 36.1 fb-1 of pp collisions at s=13TeV recorded by the ATLAS experiment at the LHC is used. The H→cc signature is identified using charm-tagging algorithms. The observed (expected) upper limit on σ(pp→ZH)×B(H→cc) is 2.7 (3.9-1.1+2.1) pb at the 95% confidence level for a Higgs boson mass of 125 GeV, while the standard model value is 26 fb. © 2018 CERN.
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| 785. |
- Milstead, David A., et al.
(författare)
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Search for the Dimuon Decay of the Higgs Boson in pp Collisions at s =13 TeV with the ATLAS Detector
- 2017
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Ingår i: Physical Review Letters. - : American Physical Society. - 1079-7114 .- 0031-9007. ; 119:5
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Tidskriftsartikel (refereegranskat)abstract
- A search for the dimuon decay of the Higgs boson was performed using data corresponding to an integrated luminosity of 36.1 fb-1 collected with the ATLAS detector in pp collisions at s=13 TeV at the Large Hadron Collider. No significant excess is observed above the expected background. The observed (expected) upper limit on the cross section times branching ratio is 3.0 (3.1) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125 GeV. When combined with the pp collision data at s=7 TeV and s=8 TeV, the observed (expected) upper limit is 2.8 (2.9) times the Standard Model prediction. © 2017 CERN.
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| 786. |
- Milstead, David A., et al.
(författare)
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Search for the Production of a Long-Lived Neutral Particle Decaying within the ATLAS Hadronic Calorimeter in Association with a Z Boson from pp Collisions at s =13 TeV
- 2019
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 1079-7114 .- 0031-9007. ; 122:15
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Tidskriftsartikel (refereegranskat)abstract
- This Letter presents a search for the production of a long-lived neutral particle (Zd) decaying within the ATLAS hadronic calorimeter, in association with a standard model (SM) Z boson produced via an intermediate scalar boson, where Z→+ (=e, μ). The data used were collected by the ATLAS detector during 2015 and 2016 pp collisions with a center-of-mass energy of s=13 TeV at the Large Hadron Collider and correspond to an integrated luminosity of 36.1±0.8 fb-1. No significant excess of events is observed above the expected background. Limits on the production cross section of the scalar boson times its decay branching fraction into the long-lived neutral particle are derived as a function of the mass of the intermediate scalar boson, the mass of the long-lived neutral particle, and its cτ from a few centimeters to one hundred meters. In the case that the intermediate scalar boson is the SM Higgs boson, its decay branching fraction to a long-lived neutral particle with a cτ approximately between 0.1 and 7 m is excluded with a 95% confidence level up to 10% for mZd between 5 and 15 GeV. © 2019 CERN for the ATLAS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 .
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| 787. |
- Milstead, David A., et al.
(författare)
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Search for W′ → tb decays in the hadronic final state using pp collisions at s=13TeV with the ATLAS detector
- 2018
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 781, s. 327-348
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Tidskriftsartikel (refereegranskat)abstract
- A search for W′-boson production in the W′→tb¯→qq¯′bb¯ decay channel is presented using 36.1fb−1 of 13 TeV proton–proton collision data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search is interpreted in terms of both a left-handed and a right-handed chiral W′ boson within the mass range 1–5 TeV. Identification of the hadronically decaying top quark is performed using jet substructure tagging techniques based on a shower deconstruction algorithm. No significant deviation from the Standard Model prediction is observed and the results are expressed as upper limits on the W′→tb¯ production cross-section times branching ratio as a function of the W′-boson mass. These limits exclude W′ bosons with right-handed couplings with masses below 3.0 TeV and W′ bosons with left-handed couplings with masses below 2.9 TeV, at the 95% confidence level. © 2018 The Author
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| 788. |
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| 789. |
- Milstead, David A., et al.
(författare)
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Study of the material of the ATLAS inner detector for Run 2 of the LHC
- 2017
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Ingår i: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS inner detector comprises three different sub-detectors: the pixel detector, the silicon strip tracker, and the transition-radiation drift-tube tracker. The Insertable B-Layer, a new innermost pixel layer, was installed during the shutdown period in 2014, together with modifications to the layout of the cables and support structures of the existing pixel detector. The material in the inner detector is studied with several methods, using a low-luminosity s=13 TeV pp collision sample corresponding to around 2.0 nb-1 collected in 2015 with the ATLAS experiment at the LHC. In this paper, the material within the innermost barrel region is studied using reconstructed hadronic interaction and photon conversion vertices. For the forward rapidity region, the material is probed by a measurement of the efficiency with which single tracks reconstructed from pixel detector hits alone can be extended with hits on the track in the strip layers. The results of these studies have been taken into account in an improved description of the material in the ATLAS inner detector simulation, resulting in a reduction in the uncertainties associated with the charged-particle reconstruction efficiency determined from simulation. © 2017 CERN.
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| 790. |
- Milstead, David A., et al.
(författare)
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Study of the rare decays of B s 0 and B 0 mesons into muon pairs using data collected during 2015 and 2016 with the ATLAS detector
- 2019
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Ingår i: Journal of High Energy Physics. - : Springer. - 1029-8479 .- 1126-6708. ; 2019:4
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Tidskriftsartikel (refereegranskat)abstract
- A study of the decays B s 0 → μ + μ − and B 0 → μ + μ − has been performed using 26.3 fb −1 of 13 TeV LHC proton-proton collision data collected with the ATLAS detector in 2015 and 2016. Since the detector resolution in μ + μ − invariant mass is comparable to the B s 0 -B 0 mass difference, a single fit determines the signal yields for both decay modes. This results in a measurement of the branching fraction ℬ(Bs0→μ+μ−)=(3.2−1.0+1.1)×10−9 and an upper limit ℬ (B→ μ + μ − ) < 4.3 × 10 − 10 at 95% confidence level. The result is combined with the Run 1 ATLAS result, yielding ℬ(Bs0→μ+μ−)=(2.8−0.7+0.8)×10−9 and ℬ (B→ μ + μ − ) < 2.1 × 10 − 10 at 95% confidence level. The combined result is consistent with the Standard Model prediction within 2.4 standard deviations in the ℬ(B0→μ+μ−)−ℬ(Bs0→μ+μ−) plane.[Figure not available: see fulltext.] © 2019, The Author(s).
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