C. G. Ames
A5080082167- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Distributed and Parallel Computing Systems
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Advanced Data Storage Technologies
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Big Data Technologies and Applications
- Advanced X-ray and CT Imaging
- Particle Accelerators and Free-Electron Lasers
- Biomedical Text Mining and Ontologies
- Nutrition, Genetics, and Disease
- Black Holes and Theoretical Physics
- Bioinformatics and Genomic Networks
Ludwig-Maximilians-Universität München
2023-2025
Sanofi (United States)
2025
Target (United States)
2025
Government of Catalonia
2024
A. Alikhanyan National Laboratory
2024
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
2023-2024
Atlas Scientific (United States)
2024
The University of Adelaide
2022-2023
Abstract The standard model of particle physics 1–4 describes the known fundamental particles and forces that make up our Universe, with exception gravity. One central features is a field permeates all space interacts 5–9 . quantum excitation this field, as Higgs manifests itself boson, only no spin. In 2012, properties consistent boson was observed by ATLAS CMS experiments at Large Hadron Collider CERN 10,11 Since then, more than 30 times many bosons have been recorded experiment, enabling...
The flavour-tagging algorithms developed by the ATLAS Collaboration and used to analyse its dataset of $\sqrt s = 13$ TeV $pp$ collisions from Run 2 Large Hadron Collider are presented. These new tagging based on recurrent deep neural networks, their performance is evaluated in simulated collision events. developments yield considerable improvements over previous jet-flavour identification strategies. At 77% $b$-jet efficiency operating point, light-jet (charm-jet) rejection factors 170 (5)...
Many extensions of the Standard Model predict production dark matter particles at LHC. Sufficiently light may be produced in decays Higgs boson that would appear invisible to detector. This Letter presents a statistical combination searches for H $\rightarrow$ where multiple modes are considered. These performed with ATLAS detector using 139 fb$^{-1}$ proton-proton collisions centre-of-mass energy $\sqrt{s} =13$ TeV In results =7$ and 8 TeV, an upper limit on branching ratio 0.107 (0.077)...
The first evidence for the Higgs boson decay to a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>Z</a:mi></a:math> and photon is presented, with statistical significance of 3.4 standard deviations. result derived from combined analysis searches performed by ATLAS CMS Collaborations proton-proton collision datasets collected at CERN Large Hadron Collider (LHC) 2015 2018. These correspond integrated luminosities around <c:math...
Abstract The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 LHC, a luminosity ℒ = × 10 34 cm -2 s -1 was routinely achieved start fills, twice design luminosity. For 3, accelerator improvements, notably levelling, allow sustained running an instantaneous , with average up to 60 interactions per bunch crossing. has been upgraded recover single-lepton trigger thresholds while operating comfortably under 3 pileup conditions. A...
Top-quark pair production is observed in lead–lead (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>Pb</a:mi><a:mo>+</a:mo><a:mi>Pb</a:mi></a:mrow></a:math>) collisions at <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:msqrt><c:mrow><c:msub><c:mrow><c:mi>s</c:mi></c:mrow><c:mrow><c:mi>NN</c:mi></c:mrow></c:msub></c:mrow></c:msqrt><c:mo>=</c:mo><c:mn>5.02</c:mn><c:mtext> </c:mtext><c:mtext>...
This paper presents the observation of four-top-quark ($t\bar{t}t\bar{t}$) production in proton-proton collisions at LHC. The analysis is performed using an integrated luminosity 140 fb$^{-1}$ a centre-of-mass energy 13 TeV collected ATLAS detector. Events containing two leptons with same electric charge or least three (electrons muons) are selected. Event kinematics used to separate signal from background through multivariate discriminant, and dedicated control regions constrain dominant...
Constraints on the Higgs boson self-coupling are set by combining double-Higgs analyses in bb¯bb¯, bb¯τ+τ− and bb¯γγ decay channels with single-Higgs targeting γγ, ZZ⁎, WW⁎, τ+τ− bb¯ channels. The data used these were recorded ATLAS detector at LHC proton–proton collisions s=13 TeV correspond to an integrated luminosity of 126–139 fb−1. combination sets upper limit μHH<2.4 95% confidence level production cross-section normalised its Standard Model prediction. Combining analyses, assumption...
A search for the electroweak production of pairs charged sleptons or charginos decaying into two-lepton final states with missing transverse momentum is presented. Two simplified models $R$-parity-conserving supersymmetry are considered: direct pair-production ($\tilde{\ell}\tilde{\ell}$), each a lepton and $\tilde{\chi}_1^0$ neutralino, lightest $(\tilde{\chi}_1^\pm\tilde{\chi}_1^\mp)$, $W$-boson $\tilde{\chi}_1^0$. The neutralino ($\tilde{\chi}_1^0$) assumed to be supersymmetric particle...
The identification of $b$-jets, referred to as $b$-tagging, is an important part many physics analyses in the ATLAS experiment at Large Hadron Collider and accurate calibration its performance essential for high-quality results. This publication describes light-flavour jet mistagging efficiency a data sample proton-proton collision events $\sqrt{s}=13$ TeV corresponding integrated luminosity 139 fb$^{-1}$. performed $Z$ bosons produced association with jets. Due low jets, method which uses...
A search for nonresonant Higgs boson pair production in the $b\overline{b}b\overline{b}$ final state is presented. The analysis uses $126\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $pp$ collision data at $\sqrt{s}=13\text{ }\mathrm{TeV}$ collected with ATLAS detector Large Hadron Collider, and targets both gluon-gluon fusion vector-boson modes. No evidence signal found observed (expected) upper limit on cross section determined to be 5.4 (8.1) times Standard Model predicted 95%...
A search is made for potential ccc¯c¯ tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at s=13 TeV, corresponding to an integrated luminosity 140 fb−1 recorded by ATLAS experiment LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds estimated based on hybrid approach involving Monte Carlo simulations data-driven methods. Statistically significant excesses with respect backgrounds dominated single...
In a special run of the LHC with $\beta^\star = 2.5~$km, proton-proton elastic-scattering events were recorded at $\sqrt{s} 13~$TeV an integrated luminosity $340~\mu \textrm{b}^{-1}$ using ALFA subdetector ATLAS in 2016. The elastic cross section was measured differentially Mandelstam $t$ variable range from $-t 2.5 \cdot 10^{-4}~$GeV$^{2}$ to 0.46~$GeV$^{2}$ 6.9 million candidates. This paper presents measurements total $\sigma_{\textrm{tot}}$, parameters nuclear slope, and $\rho$-parameter...
Differential and double-differential distributions of kinematic variables leptons from decays top-quark pairs ($t\bar{t}$) are measured using the full LHC Run 2 data sample collected with ATLAS detector. The were at a $pp$ collision energy $\sqrt{s}=13$ TeV correspond to an integrated luminosity 140 fb$^{-1}$. measurements use events containing oppositely charged $e\mu$ pair $b$-tagged jets. results compared predictions several Monte Carlo generators. While no prediction is found be...
A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13 TeV, corresponding to an integrated luminosity 140 fb^{-1} recorded by ATLAS experiment LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds estimated based on hybrid approach involving Monte Carlo simulations data-driven methods. Statistically significant excesses with respect...
Abstract A search for pair production of doubly charged Higgs bosons ( $$H^{\pm \pm }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> </mml:math> ), each decaying into a prompt, isolated, and highly energetic leptons with the same electric charge, is presented. The uses proton–proton collision data sample at centre-of-mass energy 13 TeV corresponding to an integrated luminosity 139 fb $$^{-1}$$...
Abstract This paper presents the muon momentum calibration and performance studies for ATLAS detector based on pp collisions data sample produced at $$\sqrt{s}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 13 TeV LHC during Run 2 corresponding to an integrated luminosity of 139 $${\textrm{fb}}^{-1}$$ <mml:msup> <mml:mrow> <mml:mtext>fb</mml:mtext> </mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:msup> . An...
Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon selected from <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>140</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:msup><a:mrow><a:mi>fb</a:mi></a:mrow><a:mrow><a:mo>−</a:mo><a:mn>1</a:mn></a:mrow></a:msup></a:mrow></a:math> of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"...
Charged particle reconstruction in the presence of many simultaneous proton-proton ($pp$) collisions LHC is a challenging task for ATLAS experiment's software due to combinatorial complexity. This paper describes major changes made adapt reconstruct high-activity with an average 50 or more $pp$ interactions per bunch crossing (pile-up) promptly using available computing resources. The performance key components track chain and its dependence on pile-up are evaluated, improvement achieved...
Abstract The ATLAS trigger system is a crucial component of the experiment at LHC. It responsible for selecting events in line with physics programme. This paper presents an overview changes to and data acquisition during second long shutdown LHC, shows performance its components proton-proton collisions 2022 commissioning period as well expected heavy-ion remainder third LHC data-taking (2022–2025).
A summary of precision measurements sensitive to electroweak, QCD and quark-flavour effects performed by the ATLAS Collaboration at Large Hadron Collider is reported. The are predominantly on proton-proton ($pp$) collision data recorded a centre-of-mass energy 13 TeV taken from 2015 2018, with an integrated luminosity up 140 fb$^{-1}$, some results based $pp$ Pb+Pb lower nucleon energies. cover wide range topics, strong production particles low energies spectroscopy hadrons perturbative...
Abstract A search for a light charged Higgs boson produced in decays of the top quark, $$t \rightarrow H^{\pm } b$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>t</mml:mi> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mi>b</mml:mi> </mml:mrow> </mml:math> with $$H^{\pm cs$$ <mml:mi>c</mml:mi> <mml:mi>s</mml:mi> , is presented. This targets production top-quark pairs $$t\bar{t} Wb <mml:mover> <mml:mo>¯</mml:mo>...
In ultrarelativistic heavy ion collisions at the LHC, each nucleus acts a sources of high-energy real photons that can scatter off opposing in ultraperipheral photonuclear (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>γ</a:mi><a:mo>+</a:mo><a:mi>A</a:mi></a:math>) collisions. Hard scattering processes initiated by such provide novel method for probing nuclear parton distributions kinematic region not easily accessible to other measurements. ATLAS has measured...
The correlations between flow harmonics $v_n$ for $n=2$, 3 and 4 mean transverse momentum $[p_\mathrm{T}]$ in $^{129}$Xe+$^{129}$Xe $^{208}$Pb+$^{208}$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV 5.02 TeV, respectively, are measured using charged particles with the ATLAS detector. sensitive to shape size of initial geometry, nuclear deformation, anisotropy. effects from non-flow centrality fluctuations minimized, via a subevent cumulant method event activity selection based on particle...