Персона:
Рябов, Виктор Германович

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Научная группа

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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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Рябов

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Виктор Германович

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Теперь показываю 1 - 10 из 75

Только метаданные
Production and reconstruction of short-lived ρ(770)0, K∗(892)0, φ(1020) and Λ(1520) resonances as a function of centrality and energy in Au+Au collisions at NICA
(2020) Ivanishchev, D.; Kotov, D.; Malaev, M.; Ryabov, Y.; Riabov, V.; Рябов, Виктор Германович
© Published under licence by IOP Publishing Ltd.The short-lived resonances have proved to be very useful in the study of heavy-ion collisions at SPS, RHIC, and the LHC. Properties of these particles measured in dominant hadronic decay channels carry a wealth of information about the hadron chemistry and reaction dynamics. Resonances containing one or two strange quarks contribute to the study of the strangeness enhancement phenomenon predicted as a signature of the phase transition to quark-gluon plasma in heavy-ion collisions. Resonance integrated and differential yields are sensitive to the hadron re-scattering and regeneration in the hadronic phase. The resonance production has only scarcely been studied in heavy-ion collisions at NICA energies. These proceedings are devoted to the review of the expected properties of the resonances and their sensitivity to different stages of Au+Au collisions at √sNN = 11 GeV. Results of feasibility studies for reconstruction of ρ(770)0, K∗(892)0, φ(1020) and Λ(1520) resonances in the MPD experimental setup as a function of collision energy and centrality are presented.
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Measurement of charged pion double spin asymmetries at midrapidity in longitudinally polarized p plus p collisions at root s=510 GeV
(2020) Acharya, U.; Adare, A.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the longitudinal double spin asymmetries, A(LL), for charged pions at midrapidity (vertical bar eta vertical bar < 0.35) in longitudinally polarized p + p collisions at root s. = 510 GeV. These measurements are sensitive to the gluon spin contribution to the total spin of the proton in the parton momentum fraction x range between 0.04 and 0.09. One can infer the sign of the gluon polarization from the ordering of pion asymmetries with charge alone. The asymmetries are found to be consistent with global quantum-chromodynamics fits of deep-inelastic scattering and data at root s = 200 GeV, which show a nonzero positive contribution of gluon spin to the proton spin.
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Measurement of jet-medium interactions via direct photon-hadron correlations in Au+Au and d+Au collisions at sNN =200 GeV
(2020) Acharya, U.; Adare, A.; Afanasiev, S.; Aidala, C.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.We present direct photon-hadron correlations in 200 GeV/A Au+Au, d+Au, and p+p collisions, for direct photon pT from 5-12 GeV/c, collected by the PHENIX Collaboration in the years from 2006 to 2011. We observe no significant modification of jet fragmentation in d+Au collisions, indicating that cold nuclear matter effects are small or absent. Hadrons carrying a large fraction of the quark's momentum are suppressed in Au+Au compared to p+p and d+Au. As the momentum fraction decreases, the yield of hadrons in Au+Au increases to an excess over the yield in p+p collisions. The excess is at large angles and at low hadron pT and is most pronounced for hadrons associated with lower momentum direct photons. Comparison to theoretical calculations suggests that the hadron excess arises from medium response to energy deposited by jets.
Только метаданные
Polarization and cross section of midrapidity J /ψ production in p+p collisions at s =510 GeV
(2020) Acharya, U.; Adare, A.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.The PHENIX experiment has measured the spin alignment for inclusive J/ψ→e+e- decays in proton-proton collisions at s=510 GeV at midrapidity. The angular distributions have been measured in three different polarization frames, and the three decay angular coefficients have been extracted in a full two-dimensional analysis. Previously, PHENIX saw large longitudinal net polarization at forward rapidity at the same collision energy. This analysis at midrapidity, complementary to the previous PHENIX results, sees no sizable polarization in the measured transverse momentum range of 0.0
Только метаданные
Production of b b ¯ at forward rapidity in p+p collisions at s =510 GeV PRODUCTION of b b ¯ at FORWARD RAPIDITY ... ACHARYA U et al..
(2020) Acharya, U.; Adare, A.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
© 2020 authors.The cross section of bottom quark-antiquark (bb¯) production in p+p collisions at s=510 GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider. The results are based on the yield of high mass, like-sign muon pairs measured within the PHENIX muon arm acceptance (1.2<|y|<2.2). The bb¯ signal is extracted from like-sign dimuons by utilizing the unique properties of neutral B meson oscillation. We report a differential cross section of dσbb¯→μ±μ±/dy=0.16±0.01 (stat)±0.02 (syst)±0.02 (global) nb for like-sign muons in the rapidity and pT ranges 1.2<|y|<2.2 and pT>1 GeV/c, and dimuon mass of 5-10 GeV/c2. The extrapolated total cross section at this energy for bb¯ production is 13.1±0.6 (stat)±1.5 (syst)±2.7 (global) μb. The total cross section is compared to a perturbative quantum chromodynamics calculation and is consistent within uncertainties. The azimuthal opening angle between muon pairs from bb¯ decays and their pT distributions are compared to distributions generated using ps pythia6, which includes next-to-leading order processes. The azimuthal correlations and pair pT distribution are not very well described by pythia calculations, but are still consistent within uncertainties. Flavor creation and flavor excitation subprocesses are favored over gluon splitting.
Только метаданные
Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions
(2019) Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
The PHENIX collaboration presents first measurements of low-momentum (0.4 < p(T) < 3 GeV/c) direct-photon yields from Au + Au collisions at root s(NN) =39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au +horn Au collisions at root s(NN) =200. Analyzing the photon yield as a function of the experimental observable dN(ch)/d(eta) eveals that the low-momentum (> 1 GeV= c) direct-photon yield dN(gamma)(dir)/d(eta) is a smooth function f dN(ch)/d eta and can be well described as proportional to (dN(ch)/d(eta))(alpha) with a approximate to 1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A thorn A collision systems. At a given beam energy, the scaling also holds for high p(T) (> 5 GeV= c), but when results from different collision energies are compared, an additional root s(NN) -dependent multiplicative factor is needed to describe the integrated-direct-photon yield.
Только метаданные
Nuclear Dependence of the Transverse Single-Spin Asymmetry in the Production of Charged Hadrons at Forward Rapidity in Polarized p plus p, p plus Al, and p plus Au Collisions at root s(NN)=200 GeV
(2019) Aidala, C.; Akiba, Y.; Alfred, M.; Andrieux, V.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
We report on the nuclear dependence of transverse single-spin asymmetries (TSSAs) in the production of positively charged hadrons in polarized p(up arrow) + p, p(up arrow) + Al, and p(up arrow) + Au collisions at root s(NN) = 200 GeV. The measurements have been performed at forward rapidity (1.4 < eta < 2.4) over the range of transverse momentum (1.8 < p(T) < 7.0 GeV/c) and Feynman x (0.1 < x(F) < 0.2). We observed positive asymmetries for positively charged hadrons in p(up arrow) + p collisions, and significantly reduced asymmetries in p(up arrow) + A collisions. These results reveal a nuclear dependence of TSSAs for charged-hadron production in a regime where perturbative techniques are applicable. These results provide new opportunities to use p(up arrow) + A collisions as a tool to investigate the rich phenomena behind TSSAs in hadronic collisions and to use TSSAs as a new handle in studying small-system collisions.
Только метаданные
Measurement of charm and bottom production from semileptonic hadron decays in p plus p collisions at root s=200 GeV
(2019) Aidala, C.; Akiba, Y.; Alfred, M.; Andrieux, V.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
Measurements of the differential production of electrons from open-heavy-flavor hadrons with charm-and bottom-quark content in p + p collisions at root s = 200 GeV are presented. The measurements proceed through displaced-vertex analyses of electron tracks from the semileptonic decay of charm and bottom hadrons using the PHENIX silicon-vertex detector. The relative contribution of electrons from bottom decays to inclusive heavy-flavor-electron production is found to be consistent with fixed-order-plus-next-to-leading-log perturbative-QCD calculations within experimental and theoretical uncertainties. These new measurements in p + p collisions provide a precision baseline for comparable forthcoming measurements in A + A collisions.
Только метаданные
Measurement of two-particle correlations with respect to second- and third-order event planes in Au plus Au collisions at root s(NN)=200 GeV
(2019) Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
We present measurements of azimuthal correlations of charged hadron pairs in root s(NN) = 200 GeV Au + Au collisions for the trigger and associated particle transverse-momentum ranges of 1 < p(T)(t) < 10 GeV/c and 0.5 < p(T)(a) < 10 GeV/c. After subtraction of an underlying event using a model that includes higher-order azimuthal anisotropy v(2), v(3,) and v(4), the away-side yield of the highest trigger-p(T)(p(T)(t) > 4 GeV/c) correlations is suppressed compared with that of correlations measured in p + p collisions. At the lowest associated particle p(T)(0.5 < p(T)(a) < 1 GeV/c), the away-side shape and yield are modified relative to those in p + p collisions. These observations are consistent with the scenario of radiative-jet energy loss. For the low-p(T) trigger correlations (2 < p(T)(t) < 4 GeV/c), a finite away-side yield exists and we explore the dependence of the shape of the away-side within the context of an underlying-event model. Correlations are also studied differentially versus event-plane angle Psi(2) and Psi(3). The angular correlations show an asymmetry when selecting the sign of the difference between the trigger-particle azimuthal angle and the Psi(2) event plane. This asymmetry and the measured suppression of the pair yield out-of-plane is consistent with a path-length-dependent energy loss. No Psi(3) dependence can be resolved within experimental uncertainties.
Только метаданные
Implications for small-system collectivity from a comprehensive set of soft physics measurements in 200 GeV p plus Au collisions by PHENIX
(2019) Xu, Q.; Adare, A.; Afanasiev, S.; Aidala, C.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
Proton-nucleus (p+A) collisions play an important role as a control system for interpreting hot nuclear matter effects in nucleus-nucleus (A+A) collisions. There is a large amount of data from both RHIC and the LHC that indicate that collective effects are also present in small systems. Understanding the origin of these effects is still incomplete, since a variety of models with very different underlying physics have been shown to describe p+A data. We present a comprehensive set of measurements of soft-physics observables and comparisons with theoretical models. These measurements include multi-particle correlations as a function of event multiplicity, v(2)(p(T)) and v(3)(p(T)) for inclusive charged particles at mid-rapidity, v(2)(p(T)) for hadrons at forward/backward rapidities, and the centrality and pseudorapidity dependence of inclusive v(2). The implications for the origin of collectivity in p+Au collisions at RHIC is discussed.