| 1. |
- Aaboud, M, et al.
(author)
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ATLAS Collaboration
- 2017
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In: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 967, s. 942-964
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Journal article (peer-reviewed)
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| 2. |
- Aaboud, M, et al.
(author)
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ATLAS Collaboration
- 2019
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In: XXVIIth International Conference on Ultrarelativistic Nucleus–Nucleus Collisions (Quark Matter 2018). - 0375-9474. ; 982, s. 985-1009
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Conference paper (peer-reviewed)
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| 3. |
- Aaboud, M, et al.
(author)
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Combined measurement of differential and total cross sections in the H → γγ and the H → ZZ⁎ → 4ℓ decay channels at s=13 TeV with the ATLAS detector
- 2018
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 786, s. 114-133
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Journal article (peer-reviewed)abstract
- A combined measurement of differential and inclusive total cross sections of Higgs boson production is performed using 36.1 fb−1 of 13 TeV proton–proton collision data produced by the LHC and recorded by the ATLAS detector in 2015 and 2016. Cross sections are obtained from measured H→γγ and H→ZZ⁎→4ℓ event yields, which are combined taking into account detector efficiencies, resolution, acceptances and branching fractions. The total Higgs boson production cross section is measured to be 57.0−5.9 +6.0 (stat.) −3.3 +4.0 (syst.) pb, in agreement with the Standard Model prediction. Differential cross-section measurements are presented for the Higgs boson transverse momentum distribution, Higgs boson rapidity, number of jets produced together with the Higgs boson, and the transverse momentum of the leading jet. The results from the two decay channels are found to be compatible, and their combination agrees with the Standard Model predictions. © 2018 The Author(s)
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| 4. |
- Aaboud, M, et al.
(author)
-
Constraints on mediator-based dark matter and scalar dark energy models using √s = 13 TeV pp collision data collected by the ATLAS detector
- 2019
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In: Journal of High Energy Physics. - 1029-8479. ; 2019:5
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Journal article (peer-reviewed)abstract
- Constraints on selected mediator-based dark matter models and a scalar dark energy model using up to 37 fb−1s = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016 are summarised in this paper. The results of experimental searches in a variety of final states are interpreted in terms of a set of spin-1 and spin-0 single-mediator dark matter simplified models and a second set of models involving an extended Higgs sector plus an additional vector or pseudo-scalar mediator. The searches considered in this paper constrain spin-1 leptophobic and leptophilic mediators, spin-0 colour-neutral and colour-charged mediators and vector or pseudo-scalar mediators embedded in extended Higgs sector models. In this case, also s = 8 TeV pp collision data are used for the interpretation of the results. The results are also interpreted for the first time in terms of light scalar particles that could contribute to the accelerating expansion of the universe (dark energy).[Figure not available: see fulltext.]. © 2019, The Author(s).
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| 5. |
- Aaboud, M, et al.
(author)
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Fluctuations of anisotropic flow in Pb+Pb collisions at √sNN = 5.02 TeV with the ATLAS detector
- 2020
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In: Journal of High Energy Physics. - 1029-8479. ; 2020:1
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Journal article (peer-reviewed)abstract
- Multi-particle azimuthal cumulants are measured as a function of centrality and transverse momentum using 470 μb−1 of Pb+Pb collisions at sNN = 5.02 TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of harmonic flow coefficients vn and correlated fluctuations between two harmonics vn and vm. For the first time, a non-zero four-particle cumulant is observed for dipolar flow, v1. The four-particle cumulants for elliptic flow, v2, and triangular flow, v3, exhibit a strong centrality dependence and change sign in ultra-central collisions. This sign change is consistent with significant non-Gaussian fluctuations in v2 and v3. The four-particle cumulant for quadrangular flow, v4, is found to change sign in mid-central collisions. Correlations between two harmonics are studied with three- and four-particle mixed-harmonic cumulants, which indicate an anti-correlation between v2 and v3, and a positive correlation between v2 and v4. These correlations decrease in strength towards central collisions and either approach zero or change sign in ultra-central collisions. To investigate the possible flow fluctuations arising from intrinsic centrality or volume fluctuations, the results are compared between two different event classes used for centrality definitions. In peripheral and mid-central collisions where the cumulant signals are large, only small differences are observed. In ultra-central collisions, the differences are much larger and transverse momentum dependent. These results provide new information to disentangle flow fluctuations from the initial and final states, as well as new insights on the influence of centrality fluctuations. [Figure not available: see fulltext.]. © 2020, The Author(s).
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| 6. |
- Aaboud, M, et al.
(author)
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Measurement of colour flow using jet-pull observables in tt¯ events with the ATLAS experiment at √s=13TeV
- 2018
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 78:10
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Journal article (peer-reviewed)abstract
- Previous studies have shown that weighted angular moments derived from jet constituents encode the colour connections between partons that seed the jets. This paper presents measurements of two such distributions, the jet-pull angle and jet-pull magnitude, both of which are derived from the jet-pull angular moment. The measurement is performed in tt¯ events with one leptonically decaying W boson and one hadronically decaying W boson, using 36.1fb-1 of pp collision data recorded by the ATLAS detector at s=13TeV delivered by the Large Hadron Collider. The observables are measured for two dijet systems, corresponding to the colour-connected daughters of the W boson and the two b-jets from the top-quark decays, which are not expected to be colour connected. To allow the comparison of the measured distributions to colour model predictions, the measured distributions are unfolded to particle level, after correcting for experimental effects introduced by the detector. While good agreement can be found for some combinations of predictions and observables, none of the predictions describes the data well across all observables. © 2018, CERN for the benefit of the ATLAS collaboration.
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| 7. |
- Aaboud, M, et al.
(author)
-
Measurement of fiducial and differential W+W- production cross-sections at √s=13 TeV with the ATLAS detector
- 2019
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:10
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Journal article (peer-reviewed)abstract
- A measurement of fiducial and differential cross-sections for W+W- production in proton–proton collisions at s=13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 36.1 fb - 1 is presented. Events with one electron and one muon are selected, corresponding to the decay of the diboson system as WW→ e±νμ∓ν. To suppress top-quark background, events containing jets with a transverse momentum exceeding 35 GeV are not included in the measurement phase space. The fiducial cross-section, six differential distributions and the cross-section as a function of the jet-veto transverse momentum threshold are measured and compared with several theoretical predictions. Constraints on anomalous electroweak gauge boson self-interactions are also presented in the framework of a dimension-six effective field theory. © 2019, CERN for the benefit of the ATLAS collaboration.
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| 8. |
- Aaboud, M, et al.
(author)
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Measurement of jet pT correlations in Pb + Pb and pp collisions at sNN=2.76 TeVwith the ATLAS detector
- 2017
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 379-402
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Journal article (peer-reviewed)abstract
- Measurements of dijet pT correlations in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of sNN=2.76 TeV are presented. The measurements are performed with the ATLAS detector at the Large Hadron Collider using Pb+Pb and pp data samples corresponding to integrated luminosities of 0.14 nb−1 and 4.0 pb−1, respectively. Jets are reconstructed using the anti-kt algorithm with radius parameter values R=0.3 and R=0.4. A background subtraction procedure is applied to correct the jets for the large underlying event present in Pb+Pb collisions. The leading and sub-leading jet transverse momenta are denoted pT1 and pT2. An unfolding procedure is applied to the two-dimensional (pT1,pT2) distributions to account for experimental effects in the measurement of both jets. Distributions of (1/N)dN/dxJ, where xJ=pT2/pT1, are presented as a function of pT1 and collision centrality. The distributions are found to be similar in peripheral Pb+Pb collisions and pp collisions, but highly modified in central Pb+Pb collisions. Similar features are present in both the R=0.3 and R=0.4 results, indicating that the effects of the underlying event are properly accounted for in the measurement. The results are qualitatively consistent with expectations from partonic energy loss models. © 2017 The Author
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| 9. |
- Aaboud, M, et al.
(author)
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Measurement of lepton differential distributions and the top quark mass in tt¯ production in pp collisions at √s=8 TeV with the ATLAS detector
- 2017
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:11
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Journal article (peer-reviewed)abstract
- This paper presents single lepton and dilepton kinematic distributions measured in dileptonic tt¯ events produced in 20.2fb - 1 of s=8 TeV pp collisions recorded by the ATLAS experiment at the LHC. Both absolute and normalised differential cross-sections are measured, using events with an opposite-charge eμ pair and one or two b-tagged jets. The cross-sections are measured in a fiducial region corresponding to the detector acceptance for leptons, and are compared to the predictions from a variety of Monte Carlo event generators, as well as fixed-order QCD calculations, exploring the sensitivity of the cross-sections to the gluon parton distribution function. Some of the distributions are also sensitive to the top quark pole mass; a combined fit of NLO fixed-order predictions to all the measured distributions yields a top quark mass value of mtpole=173.2±0.9±0.8±1.2 GeV, where the three uncertainties arise from data statistics, experimental systematics, and theoretical sources. © 2017, CERN for the benefit of the ATLAS collaboration.
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| 10. |
- Aaboud, M, et al.
(author)
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Measurement of prompt photon production in sNN=8.16 TeV p + Pb collisions with ATLAS
- 2019
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 796, s. 230-252
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Journal article (peer-reviewed)abstract
- The inclusive production rates of isolated, prompt photons in p+Pb collisions at sNN=8.16 TeV are studied with the ATLAS detector at the Large Hadron Collider using a dataset with an integrated luminosity of 165 nb−1 recorded in 2016. The cross-section and nuclear modification factor RpPb are measured as a function of photon transverse energy from 20 GeV to 550 GeV and in three nucleon–nucleon centre-of-mass pseudorapidity regions, (−2.83,−2.02), (−1.84,0.91), and (1.09,1.90). The cross-section and RpPb values are compared with the results of a next-to-leading-order perturbative QCD calculation, with and without nuclear parton distribution function modifications, and with expectations based on a model of the energy loss of partons prior to the hard scattering. The data disfavour a large amount of energy loss and provide new constraints on the parton densities in nuclei. © 2019 The Author
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