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Antonov, A.

Publications and source records attributed to Antonov, A..

At least 19 records

Erratum to: Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector

One correction is noted for the paper. The branching fraction ($\mathcal{B}$($W →{ℓv}$) = 0.3246 was not included in the conversion of the observed cross-section limit, σ x $\mathcal{B}$( $t →Wb$) x ($\mathcal{B}$($W →{ℓv}$) < 2.9to the coupling constants $κ_{ugt}$ and $κ_{cgt}$ and the branching fractions $\mathcal{B}$( $t →ug$) and $\mathcal{B}$( $t →cg$). The inclusion leads to weaker observed exclusion limits on the coupling constants divided by the scale of new physics of $k_{ugt}$/ Λ <10 x 10 -3 TeV -1 and $k_{cgt}$/Λ <23 x 10 -3 TeV -1 and on the branching fractions $\mathcal{B}$( $t →ug$) < 1.2 x10 -4 and $\mathcal{B}$( $t →cg$) < 6.4 x 10 -4 . The predicted exclusion limits on the coupling constants divided by the scale of new physics are $k_{ugt}$/ Λ < 9.5 x 10 -3 TeV -1 and $\mathcal{B}$( $t →cg$)/ Λ < 22 x 10 -3 TeV -1 and on the branching fractions $\mathcal{B}$( $t →ug$) < 1.1 x 10 -4 and $\mathcal{B}$( $t →cg$) < 5.7 x 10 -4 . Updated distributions of the observed upper limits on the coupling constants for combinations of cgt and ugt channels are shown in Figure 10a and on the branching fractions in Figure 10b.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Erratum to: Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb -1 of $ \sqrt{s} $ = 13 TeV pp collision data with the ATLAS detector

One correction is made to the figure 4e of the paper. The reported cross-sections, both the experimental upper limits and the theoretical prediction, corresponded only to a fiducial region of the phase space with at least two prompt same-sign electrons or muons before detector simulation (p T > 10 GeV, |η| < 2.8). The updated figure 4e instead presents the results without this requirement, i.e. in the full phase space as it should, given the y-axis label of the plot. The reported sensitivity of the analysis, i.e. the ability to exclude top squark masses below 700 GeV in this scenario, is however unchanged since the same requirements were applied to the analysis and to the theory predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Erratum to: Measurement of the W boson polarisation in $t\bar{t}$ events from pp collisions at $\sqrt{s} = 8~\hbox {TeV}$ in the lepton + jets channel with ATLAS

A bug in the code used to calculate the total correlation coefficients between the W boson helicity fractions obtained using the leptonic analyser in semileptonic $t\bar{t}$ events in the region with ≥ 2 b -tags was found. It led to quoting incorrect correlation coefficients in the original paper.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Search for electroweak production of supersymmetric particles in final states with two or three leptons at $\sqrt{s}=13 \hbox {TeV}$ with the ATLAS detector

A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb -1 of √s=13 TeV proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge bosons; direct production of chargino pairs, which in turn decay into leptons and the lightest neutralino via intermediate sleptons; and slepton pair production, where each slepton decays directly into the lightest neutralino and a lepton. No significant deviations from the Standard Model expectation are observed and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles in each of these scenarios. For a massless lightest neutralino, masses up to 580 GeV are excluded for the associated production of the next-to-lightest neutralino and the lightest chargino, assuming gauge-boson mediated decays, whereas for slepton-pair production masses up to 500 GeV are excluded assuming three generations of mass-degenerate sleptons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurements of differential cross sections of top quark pair production in association with jets in pp collisions at $\sqrt{s}=13 $ TeV using the ATLAS detector

Measurements of differential cross sections of top quark pair production in association with jets by the ATLAS experiment at the LHC are presented. The measurements are performed as functions of the top quark transverse momentum, the transverse momentum of the top quark-antitop quark system and the out-of-plane transverse momentum using data from pp collisions at s√=13 TeV collected by the ATLAS detector at the LHC in 2015 and corresponding to an integrated luminosity of 3.2 fb -1 . The top quark pair events are selected in the lepton (electron or muon) + jets channel. The measured cross sections, which are compared to several predictions, allow a detailed study of top quark production.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurement of colour flow using jet-pull observables in $t\bar{t}$ events with the ATLAS experiment at $\sqrt{s} = 13\,\hbox {TeV}$

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 $t\bar{t}$ 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√=13 TeV 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.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Angular analysis of B$0\atop{d}$ → K*μ + μ - decays in pp collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

An angular analysis of the decay B$0\atop{d}$ → K*μ + μ - is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC. The study is using 20.3 fb -1 of integrated luminosity collected during 2012 at centre-of-mass energy of $\sqrt{s}=8 $ TeV. Measurements of the K* longitudinal polarisation fraction and a set of angular parameters obtained for this decay are presented. The results are compatible with the Standard Model predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗