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Смирнов, Сергей Юрьевич

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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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Смирнов

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Сергей Юрьевич

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Measurement of azimuthal anisotropy of muons from charm and bottom hadrons in Pb+Pb collisions at sNN=5.02 TeV with the ATLAS detector
(2020) Aad, G.; Abbott, B.; Abbott, D. C.; Abed, Abud, A.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kurova, A.; Ponomarenko, D.; Proklova, N.; 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; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович
© 2020 The Author(s)Azimuthal anisotropies of muons from charm and bottom hadron decays are measured in Pb+Pb collisions at sNN=5.02TeV. The data were collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2018 with integrated luminosities of 0.5nb−1 and 1.4nb−1, respectively. The kinematic selection for heavy-flavor muons requires transverse momentum 4
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Studies of the spectral and angular distributions of transition radiation using a silicon pixel sensor on a Timepix3 chip
(2020) Alozy, J.; Campbell, M.; Cherry, M.; Dachs, F.; Belyaev, N.; Doronin, S.; Filippov, K.; Krasnopevtsev, D.; Ponomarenko, D.; Romaniouk, A.; Savchenko, A. A.; Sergeeva, D. Y.; Shulga, E.; Smirnov, S.; Smirnov, Y.; Strikhanov, M.; Teterin, P.; Tishchenko, A. A.; Vorobev, K.; Доронин, Семен Александрович; Романюк, Анатолий Самсонович; Савченко, Александр Алексеевич; Сергеева, Дарья Юрьевна; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Стриханов, Михаил Николаевич; Тетерин, Пётр Евгеньевич; Тищенко, Алексей Александрович; Воробьёв, Константин Александрович
© 2020 Elsevier B.V.X-ray transition radiation detectors (TRDs) are used for particle identification in both high energy physics and astroparticle physics. In most of the detectors, emission of the X-ray transition radiation (TR) starts at Lorentz factors above γ∼500 and reaches saturation at γ∼2÷3⋅103. However, many experiments require particle identification up to γ∼105, which is very difficult to achieve with conventional detectors. Semiconductor pixel detectors offer a unique opportunity for precise simultaneous measurements of spectral and angular parameters of TR photons. Test beam studies of the energy and the angular distributions of TR photons emitted by electrons and muons of different momenta crossing several types of radiators were performed at the CERN SPS with a 480 μm thick silicon detector bonded to a Timepix3 chip. High resolution images of the energy−angle phase space of the TR produced by different radiators were obtained and compared with MC simulations. The characteristic interference patterns are in agreement with the theoretical models with an unprecedented level of details. The studies presented in this paper also show that simultaneous measurements of both the energy and the emission angles of the TR X-rays could be used to enhance the particle identification performances of TRDs.
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Measurements of inclusive and differential fiducial cross-sections of tt¯ production with additional heavy-flavour jets in proton-proton collisions at √s = 13 TeV with the ATLAS detector
(2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Kurova, A.; Ponomarenko, D.; Proklova, N.; Romaniouk, A.; Shulga, E.; 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
© 2019, The Author(s). This paper presents measurements of tt¯ production in association with additional b-jets in pp collisions at the LHC at a centre-of-mass energy of 13 TeV. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.1 fb −1 . Fiducial cross-section measurements are performed in the dilepton and lepton-plus-jets tt¯ decay channels. Results are presented at particle level in the form of inclusive cross-sections of tt¯ final states with three and four b-jets as well as differential cross-sections as a function of global event properties and properties of b-jet pairs. The measured inclusive fiducial cross-sections generally exceed the tt¯ bb¯ predictions from various next-to-leading-order matrix element calculations matched to a parton shower but are compatible within the total uncertainties. The experimental uncertainties are smaller than the uncertainties in the predictions. Comparisons of state-of-the-art theoretical predictions with the differential measurements are shown and good agreement with data is found for most of them.[Figure not available: see fulltext.].
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Study of the hard double-parton scattering contribution to inclusive four-lepton production in pp collisions at s=8 TeV with the ATLAS detector
(2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Belotskiy, K.; Belyaev, N. L.; Bulekov, O.; Kantserov, V. A.; Kurova, 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; Курова, Анастасия Сергеевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович
© 2019 The Author(s) The inclusive production of four isolated charged leptons in pp collisions is analysed for the presence of hard double-parton scattering, using 20.2 fb −1 of data recorded in the ATLAS detector at the LHC at centre-of-mass energy s=8 TeV. In the four-lepton invariant-mass range of 80
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Measurement of photon–jet transverse momentum correlations in 5.02 TeV Pb + Pb and pp collisions with ATLAS
(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
© 2018 The Author(s) Jets created in association with a photon can be used as a calibrated probe to study energy loss in the medium created in nuclear collisions. Measurements of the transverse momentum balance between isolated photons and inclusive jets are presented using integrated luminosities of 0.49 nb−1 of Pb + Pb collision data at sNN=5.02 TeV and 25 pb−1 of pp collision data at s=5.02 TeV recorded with the ATLAS detector at the LHC. Photons with transverse momentum 63.131.6 GeV and pseudorapidity |ηjet|<2.8. The transverse momentum balance given by the jet-to-photon pT ratio, xJγ, is measured for pairs with azimuthal opening angle Δϕ>7π/8. Distributions of the per-photon jet yield as a function of xJγ, (1/Nγ)(dN/dxJγ), are corrected for detector effects via a two-dimensional unfolding procedure and reported at the particle level. In pp collisions, the distributions are well described by Monte Carlo event generators. In Pb + Pb collisions, the xJγ distribution is modified from that observed in pp collisions with increasing centrality, consistent with the picture of parton energy loss in the hot nuclear medium. The data are compared with a suite of energy-loss models and calculations.
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Fine structure of angular distribution of x-ray transition radiation from multilayered radiator in Geant4
(2020) Cherry, M.; Dachs, F.; Fusco, P.; Gargano, F.; Savchenko, A. A.; Tishchenko, A. A.; Sergeeva, D. Y.; Belyaev, N.; Doronin, S.; Filippov, K.; Nechaeva, S.; Ponomarenko, D.; Romaniouk, A.; Smirnov, S.; Smirnov, Y.; Strikhanov, M. N.; Teterin, P.; Vorobev, K.; Савченко, Александр Алексеевич; Тищенко, Алексей Александрович; Сергеева, Дарья Юрьевна; Доронин, Семен Александрович; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Стриханов, Михаил Николаевич; Тетерин, Пётр Евгеньевич; Воробьёв, Константин Александрович
© 2020 IOP Publishing Ltd and Sissa Medialab.The present version of the Transition Radiation (TR) simulation module implemented in the Geant4 toolkit describes very well experimental data for the TR energy distribution; however, it does not allow reproducing the details of angular distribution at small angles. In order to solve this problem, corrections to the existing x-ray TR module in Geant4 are proposed. With these corrections, the results of the simulations are in a good agreement with the angular TR distributions predicted by theory and obtained in the test beam measurements using a 480 um Si pixel detector and Mylar radiator.
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Measurements 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.
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In 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
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Search for heavy charged long-lived particles in proton–proton collisions at s=13TeV using an ionisation measurement 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
© 2018 The Author This Letter presents a search for heavy charged long-lived particles produced in proton–proton collisions at s=13TeV at the LHC using a data sample corresponding to an integrated luminosity of 36.1fb−1 collected by the ATLAS experiment in 2015 and 2016. These particles are expected to travel with a velocity significantly below the speed of light, and therefore have a specific ionisation higher than any high-momentum Standard Model particle of unit charge. The pixel subsystem of the ATLAS detector is used in this search to measure the ionisation energy loss of all reconstructed charged particles which traverse the pixel detector. Results are interpreted assuming the pair production of R-hadrons as composite colourless states of a long-lived gluino and Standard Model partons. No significant deviation from Standard Model background expectations is observed, and lifetime-dependent upper limits on R-hadron production cross-sections and gluino masses are set, assuming the gluino always decays to two quarks and a 100 GeV stable neutralino. R-hadrons with lifetimes above 1.0 ns are excluded at the 95% confidence level, with lower limits on the gluino mass ranging between 1290 GeV and 2060 GeV. In the case of stable R-hadrons, the lower limit on the gluino mass at the 95% confidence level is 1890 GeV.
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Electron and photon energy calibration with the ATLAS detector using 2015-2016 LHC proton-proton collision data
(2019) 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.; Shulga, E.; Smirnov, N.; Smirnov, S. Yu.; Smirnov, Y.; Soldatov, E. Yu.; Timoshenko, S.; Vorobev, K.; Tikhomirov, V. O.; Белоцкий, Константин Михайлович; Булеков, Олег Владимирович; Курова, Анастасия Сергеевна; Романюк, Анатолий Самсонович; Смирнов, Сергей Юрьевич; Смирнов, Юрий Сергеевич; Солдатов, Евгений Юрьевич; Тимошенко, Сергей Леонидович; Воробьёв, Константин Александрович; Тихомиров, Владимир Олегович
This paper presents the electron and photon energy calibration obtained with the ATLAS detector using about 36 fb(-1) of LHC proton-proton collision data recorded at root s = 13 TeV in 2015 and 2016. The different calibration steps applied to the data and the optimization of the reconstruction of electron and photon energies are discussed. The absolute energy scale is set using a large sample of Z boson decays into electron-positron pairs. The systematic uncertainty in the energy scale calibration varies between 0.03% to 0.2% in most of the detector acceptance for electrons with transverse momentum close to 45 GeV. For electrons with transverse momentum of 10 GeV the typical uncertainty is 0.3% to 0.8% and it varies between 0.25% and 1% for photons with transverse momentum around 60 GeV. Validations of the energy calibration with J/psi -> e(+)e(-) decays and radiative Z boson decays are also presented.