Персона: Булеков, Олег Владимирович
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Олег Владимирович
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- ПубликацияОткрытый доступSearch for light resonances decaying to boosted quark pairs and produced in association with a photon or a jet in proton–proton collisions at √s=13TeV with the ATLAS detector(2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Antonov, A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Krasnopevtsev, D.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Shulga, E.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Timoshenko, S.; Tikhomirov, V. O.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Тихомиров, Владимир Олегович; Воробьёв, Константин Александрович© 2018 The Author(s) This Letter presents a search for new light resonances decaying to pairs of quarks and produced in association with a high-pT photon or jet. The dataset consists of proton–proton collisions with an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy of s=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Resonance candidates are identified as massive large-radius jets with substructure consistent with a particle decaying into a quark pair. The mass spectrum of the candidates is examined for local excesses above background. No evidence of a new resonance is observed in the data, which are used to exclude the production of a lepto-phobic axial-vector Z′ boson.
- ПубликацияОткрытый доступIdentification of boosted Higgs bosons decaying into b-quark pairs with the ATLAS detector at 13 TeV(2019) Aad, G.; Abbott, B.; Abbott, D. C.; Abdinov, O.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович© 2019, CERN for the benefit of the ATLAS collaboration.This paper describes a study of techniques for identifying Higgs bosons at high transverse momenta decaying into bottom-quark pairs, H→ bb¯ , for proton–proton collision data collected by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy s=13 TeV. These decays are reconstructed from calorimeter jets found with the anti-ktR= 1.0 jet algorithm. To tag Higgs bosons, a combination of requirements is used: b-tagging of R= 0.2 track-jets matched to the large-R calorimeter jet, and requirements on the jet mass and other jet substructure variables. The Higgs boson tagging efficiency and corresponding multijet and hadronic top-quark background rejections are evaluated using Monte Carlo simulation. Several benchmark tagging selections are defined for different signal efficiency targets. The modelling of the relevant input distributions used to tag Higgs bosons is studied in 36 fb- 1 of data collected in 2015 and 2016 using g→ bb¯ and Z(→ bb¯) γ event selections in data. Both processes are found to be well modelled within the statistical and systematic uncertainties.
- ПубликацияОткрытый доступIn situ calibration of large-radius jet energy and mass in 13 TeV proton–proton collisions with the ATLAS detector(2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Shulga, E.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Timoshenko, S.; Vorobev, K.; Tikhomirov, V. O.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович© 2019, CERN for the benefit of the ATLAS collaboration. The response of the ATLAS detector to large-radius jets is measured in situ using 36.2 fb - 1 of s=13 TeV proton–proton collisions provided by the LHC and recorded by the ATLAS experiment during 2015 and 2016. The jet energy scale is measured in events where the jet recoils against a reference object, which can be either a calibrated photon, a reconstructed Z boson, or a system of well-measured small-radius jets. The jet energy resolution and a calibration of forward jets are derived using dijet balance measurements. The jet mass response is measured with two methods: using mass peaks formed by W bosons and top quarks with large transverse momenta and by comparing the jet mass measured using the energy deposited in the calorimeter with that using the momenta of charged-particle tracks. The transverse momentum and mass responses in simulations are found to be about 2–3% higher than in data. This difference is adjusted for with a correction factor. The results of the different methods are combined to yield a calibration over a large range of transverse momenta (p T ). The precision of the relative jet energy scale is 1–2% for 200GeV
- ПубликацияОткрытый доступMeasurements of gluon–gluon fusion and vector-boson fusion Higgs boson production cross-sections in the H → WW⁎ → eνμν decay channel in pp collisions at √s=13TeV with the ATLAS detector(2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Shulga, E.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Timoshenko, S.; Vorobev, K.; Tikhomirov, V. O.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович© 2019 The Author Higgs boson production cross-sections in proton–proton collisions are measured in the H→WW⁎→eνμν decay channel. The proton–proton collision data were produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1fb−1. The product of the H→WW⁎ branching fraction times the gluon–gluon fusion and vector-boson fusion cross-sections are measured to be 11.4−1.1 +1.2(stat.)−1.7 +1.8(syst.)pb and 0.50−0.22 +0.24(stat.)±0.17(syst.)pb, respectively, in agreement with Standard Model predictions.
- ПубликацияОткрытый доступSearch for direct production of electroweakinos in final states with one lepton, missing transverse momentum and a Higgs boson decaying into two b-jets in pp collisions at root s=13 TeV with the ATLAS detector(2020) Aad, G.; Abbott, B.; Abbott, D. C.; Abud, A. A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин АлександровичThe results of a search for electroweakino pair production pp -> (chi) over tilde (+/-)(1) (chi) over tilde (0)(2) in which the chargino ((chi) over tilde (+/-)(1)) decays into a W boson and the lightest neutralino ((chi) over tilde (0)(1)), while the heavier neutralino ((chi) over tilde (0)(2)) decays into the Standard Model 125 GeV Higgs boson and a second (chi) over tilde (0)(1) are presented. The signal selection requires a pair of b-tagged jets consistent with those from a Higgs boson decay, and either an electron or a muon from the W boson decay, together with missing transverse momentum from the corresponding neutrino and the stable neutralinos. The analysis is based on data corresponding to 139 fb(-1) of root s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. No statistically significant evidence of an excess of events above the Standard Model expectation is found. Limits are set on the direct production of the electroweakinos in simplified models, assuming pure wino cross-sections. Masses of (chi) over tilde (+/-)(1) (chi) over tilde (0)(2) up to 740 GeV are excluded at 95% confidence level for a massless (chi) over tilde (0)(1).
- ПубликацияОткрытый доступPerformance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s = 13 TeV(2021) Aad, G.; Abbott, B.; Abbott, D. C.; Abud, A. A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Pyatiizbyantseva, D.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Yu.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Пятиизбянцева, Диана Николаевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович© 2021 CERN for the benefit of the ATLAS collaboration. Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licenceThe ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m2. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb-1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC.
- ПубликацияТолько метаданныеMeasurement of the relative Bc± /B± production cross section with the ATLAS detector at s =8 TeV MEASUREMENT of the RELATIVE Bc± /B± ... AABOUD M. et al.(2021) Aaboud, M.; Aad, G.; Abbott, B.; Abbott, D. C.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович© 2021 CERN.The total cross section and differential cross sections for the production of Bc± mesons, times their branching fraction to J/ψπ±, are measured relative to those for the production of B± mesons, times their branching fraction to J/ψK±. The data used for this study correspond to an integrated luminosity of 20.3 fb-1 of pp collisions recorded by the ATLAS detector at the Large Hadron Collider in 2012 at a center-of-mass energy of s=8 TeV. The measurement is performed differentially in bins of transverse momentum pT for 13 GeV22 GeV and in bins of rapidity y for |y|<0.75 and 0.75<|y|<2.3. The relative cross section times branching fraction for the full range pT>13 GeV and |y|<2.3 is (0.34±0.04stat -0.02+0.06sys±0.01lifetime)%. The differential measurements suggest that the production cross section of the Bc± decreases faster with pT than the production cross section of the B±, while no significant dependence on rapidity is observed.
- ПубликацияТолько метаданныеTest of the universality of τ and μ lepton couplings in W-boson decays with the ATLAS detector(2021) Aad, G.; Abbott, B.; Abbott, D. C.; Abud, A. A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Pyatiizbyantseva, D.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Пятиизбянцева, Диана Николаевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович© 2021, The Author(s), under exclusive licence to Springer Nature Limited.The standard model of particle physics encapsulates our best current understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the decay rate of W bosons to τ leptons and muons, R(τ/μ), constitutes an important test of this axiom. Using 139 fb−1 of proton–proton collisions recorded with the ATLAS detector at a centre-of-mass energy of 13 TeV, we report a measurement of this quantity from di-leptonic tt¯ events where the top quarks decay into a W boson and a bottom quark. We can distinguish muons originating from W bosons and those originating from an intermediate τ lepton through the muon transverse impact parameter and differences in the muon transverse momentum spectra. The measured value of R(τ/μ) is 0.992 ± 0.013 [± 0.007(stat) ± 0.011(syst)] and is in agreement with the hypothesis of universal lepton couplings as postulated in the standard model. This is the only such measurement from the Large Hadron Collider, so far, and obtains twice the precision of previous measurements.
- ПубликацияТолько метаданныеObservation of photon-induced W+W− production in pp collisions at s=13 TeV using the ATLAS detector(2021) Aad, G.; Abbott, B.; Abbott, D. C.; Abed, Abud, A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Pyatiizbyantseva, D.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Timoshenko, S.; Vorobev, K.; Tikhomirov, V. O.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Пятиизбянцева, Диана Николаевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович© 2021 The Author(s)This letter reports the observation of photon-induced production of W-boson pairs, γγ→WW. The analysis uses 139 fb−1 of LHC proton–proton collision data taken at s=13 TeV recorded by the ATLAS experiment during the years 2015–2018. The measurement is performed selecting one electron and one muon, corresponding to the decay of the diboson system as WW→e±νμ∓ν final state. The background-only hypothesis is rejected with a significance of well above 5 standard deviations consistent with the expectation from Monte Carlo simulation. A cross section for the γγ→WW process of 3.13±0.31(stat.)±0.28(syst.) fb is measured in a fiducial volume close to the acceptance of the detector, by requiring an electron and a muon of opposite signs with large dilepton transverse momentum and exactly zero additional charged particles. This is found to be in agreement with the Standard Model prediction.
- ПубликацияТолько метаданныеMeasurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at √s=13TeV(2021) Aad, G.; Abbott, B.; Abbott, D. C.; Abud, A. A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Pyatiizbyantseva, D.; Romaniouk, A.; Smirnov, N.; Smirnov, S. Y.; Smirnov, Y.; Soldatov, E. Y.; Tikhomirov, V. O.; Timoshenko, S.; Vorobev, K.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Пятиизбянцева, Диана Николаевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тихомиров, Владимир Олегович; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович© 2021, CERN for the benefit of the ATLAS collaboration.The paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fb - 1 of s=13TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95-0.36+0.38 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.