Browsing by Author "Abeling, Kira"

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Cross-Section Measurements for the Production of a W-Boson in Association with High-Transverse Jets in pp Collisions at S = 13 TeV with the ATLAS Detector
(Springer Nature, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
A set of measurements for the production of a W-boson in association with high-transverse-momentum jets is presented using 140 fb-1 of proton–proton collision data at a centre-of-mass energy of s=13 TeV collected by the ATLAS detector at the LHC. The measurements are performed in final states in which the W-boson decays into an electron or muon plus a neutrino and is produced in association with jets with pTEMPTY>30 GeV, where the leading jet has pTEMPTY>500 GeV. The angular separation between the lepton and the closest jet with pTEMPTY>100 GeV is measured and used to define a collinear phase space, wherein measurements of kinematic properties of the W-boson and the associated jet are performed. The collinear phase space is populated by dijet events radiating a W-boson and events with a W-boson produced in association with several jets and it serves as an excellent data sample to probe higher-order theoretical predictions. Measured differential distributions are compared with predictions from state-of-the-art next-to-leading order multi-leg merged Monte Carlo event generators and a fixed-order calculation of the W+1-jet process computed at next-to-next-to-leading order in the strong coupling constant. © 2025 Elsevier B.V., All rights reserved.
Differential Cross-Section Measurements of D± and Ds± Meson Production in Proton-Proton Collisions at S = 13 TeV With the ATLAS Detector
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
The production of D± and Ds± charmed mesons is measured using the D±/Ds±→ ϕ(μμ)π± decay channel with 137 fb−1 of s = 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider during the years 2016–2018. The charmed mesons are reconstructed in the range of transverse momentum 12 < pT < 100 GeV and pseudorapidity |η| < 2.5. The differential cross-sections are measured as a function of transverse momentum and pseudorapidity, respectively, and compared with next-to-leading- order QCD predictions. The predictions are found to be consistent with the measurements in the visible kinematic region within the large theoretical uncertainties. © 2025 Elsevier B.V., All rights reserved.
Erratum to: Measurement of T-Channel Production of Single Top Quarks and Antiquarks in pp Collisions at 13 TeV Using the Full ATLAS Run 2 Data Sample (Journal of High Energy Physics, (2024), 2024, 5, (305), 10.1007/jhep05(2024)305)
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Abbott, Brad K.; Abeling, Kira; Abicht, N. J.; Abidi, Syed Hani; Aboulhorma, Asmaa; Abusleme Hoffman, A. C.
Erratum to: Search for (Formula Presented.) Production in the Multilepton Final State in Proton–Proton Collisions at (Formula Presented.) = 13 TeV with the ATLAS Detector (Journal of High Energy Physics, (2023), 2023, 7, (203), 10.1007/jhep07(2023)203)
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Abbott, Brad K.; Abbott, D. C.; Abeling, Kira; Abidi, Syed Hani; Aboulhorma, Asmaa; Abusleme Hoffman, A. C.
Correction to one figure and the corresponding numbers in the text are noted for the paper. A wrong cross-section was used for the theory prediction of t¯tA(→ t¯t), which was estimated to differ by around 1% with respect to the one of t¯tH(→ t¯t). It was found later that the production cross-section for t¯tA(→ t¯t) can be up to 60% higher than the one of t¯tH(→ t¯t) for tan β ∼ 1. This affects the theoretical prediction shown in figure 7, and the limits in the tan β vs mH/A plane shown in figure 8(a). The changes in the text are noted for sections 8 and 9. • In the scenario where the scalar H and pseudo-scalar A bosons have equal masses and both contribute to BSM t¯tt¯t production, values of tan β below 1.9 and 0.7 are excluded for mH/A between 400 GeV and 1000 GeV, respectively, at 95% CL instead of 1.6 and 0.6. • In the scenario where only the pseudo-scalar A boson contributes to BSM t¯tt¯t production, values of tan β below 1.5 and 0.5 are excluded for mA between 400 GeV and 1000 GeV, respectively, at 95% CL instead of 1.2 and 0.5. The original plot for this scenario is not included in the paper as it was nearly identical to the one where only the scalar H boson contributes to BSM t¯tt¯t production, and was therefore omitted. After correction, the updated limits in the tan β vs mA plane are shown in figure 8(c). © 2025 Elsevier B.V., All rights reserved.
Citation - Scopus: 1
Measurements of the Production Cross-Sections of a Higgs Boson in Association With a Vector Boson and Decaying Into WW* With the ATLAS Detector at S = 13 TeV
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
Measurements of the total and differential Higgs boson production cross-sections, via WH and ZH associated production using H → WW* → ℓνℓν and H → WW* → ℓνjj decays, are presented. The analysis uses proton-proton events delivered by the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector between 2015 and 2018. The data correspond to an integrated luminosity of 140 fb−1. The sum of the WH and ZH cross-sections times the H → WW* branching fraction is measured to be 0.44−0.09+0.10stat.−0.05+0.06syst. pb, in agreement with the Standard Model prediction. Higgs boson production is further characterised through measurements of the differential cross-section as a function of the transverse momentum of the vector boson and in the framework of Simplified Template Cross-Sections. © 2025 Elsevier B.V., All rights reserved.
Citation - Scopus: 7
The Performance of Missing Transverse Momentum Reconstruction and Its Significance with the ATLAS Detector Using 140 fb-1 of S=13 TeV pp Collisions
(Springer Nature, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abeling, Kira; Abicht, N. J.; Abidi, Syed Hani; Abulaiti, Yiming
This paper presents the reconstruction of missing transverse momentum (pTmiss) in proton–proton collisions, at a center-of-mass energy of 13 TeV. This is a challenging task involving many detector inputs, combining fully calibrated electrons, muons, photons, hadronically decaying τ-leptons, hadronic jets, and soft activity from remaining tracks. Possible double counting of momentum is avoided by applying a signal ambiguity resolution procedure which rejects detector inputs that have already been used. Several pTmiss ‘working points’ are defined with varying stringency of selections, the tightest improving the resolution at high pile-up by up to 39% compared to the loosest. The pTmiss performance is evaluated using data and Monte Carlo simulation, with an emphasis on understanding the impact of pile-up, primarily using events consistent with leptonic Z decays. The studies use 140fb-1 of data, collected by the ATLAS experiment at the Large Hadron Collider between 2015 and 2018. The results demonstrate that pTmiss reconstruction, and its associated significance, are well understood and reliably modelled by simulation. Finally, the systematic uncertainties on the soft pTmiss component are calculated. After various improvements the scale and resolution uncertainties are reduced by up to 76% and 51%, respectively, compared to the previous calculation at a lower luminosity. © 2025 Elsevier B.V., All rights reserved.
Citation - WoS: 6
Citation - Scopus: 8
Search for Diphoton Resonances in the 66 to 110 GeV Mass Range Using pp Collisions at (Formula Presented.) TeV with the ATLAS Detector
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Abbott, Brad K.; Abeling, Kira; Abicht, N. J.; Abidi, Syed Hani; Aboulhorma, Asmaa; Acharya, Bobby S.
A search is performed for light, spin-0 bosons decaying into two photons in the 66 to 110 GeV mass range, using 140 fb−1 of proton-proton collisions at s = 13 TeV produced by the Large Hadron Collider and collected by the ATLAS detector. Multivariate analysis techniques are used to define event categories that improve the sensitivity to new resonances beyond the Standard Model. A model-independent search for a generic spin-0 particle and a model-dependent search for an additional low-mass Higgs boson are performed in the diphoton invariant mass spectrum. No significant excess is observed in either search. Mass-dependent upper limits at the 95% confidence level are set in the model-independent scenario on the fiducial cross-section times branching ratio into two photons in the range of 8 fb to 53 fb. Similarly, in the model-dependent scenario upper limits are set on the total cross-section times branching ratio into two photons as a function of the Higgs boson mass in the range of 19 fb to 102 fb. © 2025 Elsevier B.V., All rights reserved.
Citation - WoS: 33
Citation - Scopus: 25
Search for Heavy Resonances Decaying Into a Z or W Boson and a Higgs Boson in Final States with Leptons and b-jets in 139 fb−1 of pp Collisions at √s = 13 TeV with the ATLAS Detector
(Springer Science and Business Media Deutschland GmbH, 2023) Aad, Georges; Abbott, Brad K.; Abbott, D. C.; Abeling, Kira; Abidi, Syed Hani; Aboulhorma, Asmaa; Abusleme Hoffman, A. C.
This article presents a search for new resonances decaying into a Z or W boson and a 125 GeV Higgs boson h, and it targets the νν¯ bb¯ , ℓ+ℓ−bb¯ , or ℓ±νbb¯ final states, where ℓ = e or μ, in proton-proton collisions at s = 13 TeV. The data used correspond to a total integrated luminosity of 139 fb−1 collected by the ATLAS detector during Run 2 of the LHC at CERN. The search is conducted by examining the reconstructed invariant or transverse mass distributions of Zh or Wh candidates for evidence of a localised excess in the mass range from 220 GeV to 5 TeV. No significant excess is observed and 95% confidence-level upper limits between 1.3 pb and 0.3 fb are placed on the production cross section times branching fraction of neutral and charged spin-1 resonances and CP-odd scalar bosons. These limits are converted into constraints on the parameter space of the Heavy Vector Triplet model and the two-Higgs-doublet model. [Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.
Citation - Scopus: 6
Search for Magnetic Monopole Pair Production in Ultraperipheral (Formula Presented) Collisions at (Formula Presented) With the ATLAS Detector at the LHC
(American Physical Society, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
This Letter presents a search for highly ionizing magnetic monopoles in (Formula presented) of ultraperipheral (Formula presented) collision data at (Formula presented) collected by the ATLAS detector at the LHC. A new methodology that exploits the properties of clusters of hits reconstructed in the innermost silicon detector layers is introduced to study highly ionizing particles in heavy-ion data. No significant excess above the background, which is estimated using a data-driven technique, is observed. Using a nonperturbative semiclassical model, upper limits at 95% confidence level are set on the cross section for pair production of monopoles with a single Dirac magnetic charge in the mass range of 20-150 GeV. Depending on the model, monopoles with a single Dirac magnetic charge and mass below 80-120 GeV are excluded. © 2025 Elsevier B.V., All rights reserved.
Citation - WoS: 2
Citation - Scopus: 1
Search for New Particles in Events with a Hadronically Decaying W or Z Boson and Large Missing Transverse Momentum at S = 13 TeV Using the ATLAS Detector
(Springer Science and Business Media Deutschland GmbH, 2024) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
A search is presented for new particles produced in proton-proton collisions at a centre-of-mass energy of 13 TeV that result in final states comprising a massive vector (W or Z) boson that decays hadronically and large missing transverse momentum. The data sample was collected with the ATLAS experiment at the Large Hadron Collider from 2015 to 2018 and corresponds to an integrated luminosity of 140 fb−1. No significant excess over the Standard Model expectation is observed. Model-independent 95% confidence-level limits on the visible cross-section that range from 0.3 fb to 79.5 fb are obtained for non-Standard-Model processes. Exclusion limits are also presented for models with axion-like particles, for two-Higgs-doublet models with a pseudo-scalar mediator between the Standard Model and the dark sector, for the invisible decay of the Higgs boson and for pair-produced weakly interacting dark matter candidates. © 2025 Elsevier B.V., All rights reserved.
Search for Same-Charge Top-Quark Pair Production in pp Collisions at √s = 13 TeV with the ATLAS Detector
(Springer Science and Business Media Deutschland GmbH, 2025) Aad, Georges; Aakvaag, Erlend; Abbott, Brad K.; Abdelhameed, S.; Abeling, Kira; Abicht, N. J.; Abramowicz, Halina
A search for the production of top-quark pairs with the same electric charge (tt or tt¯) is presented. The analysis uses proton-proton collision data at s = 13 TeV, recorded by the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb−1. Events with two same-charge leptons and at least two b-tagged jets are selected. Neural networks are employed to define two selections sensitive to additional couplings beyond the Standard Model that would enhance the production rate of same-sign top-quark pairs. No significant signal is observed, leading to an upper limit on the total production cross-section of same-sign top-quark pairs of 1.6 fb at 95% confidence level. Corresponding limits on the three Wilson coefficients associated with the Otu1, OQu1, and OQu8 operators in the Standard Model Effective Field Theory framework are derived. © 2025 Elsevier B.V., All rights reserved.