Персона: Рябов, Виктор Германович
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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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Виктор Германович
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- ПубликацияТолько метаданныеJ/psi and psi(2S) production at forward rapidity in p plus p collisions at root s=510 GeV(2020) Acharya, U. A.; Adare, A.; Aidala, C.; Ajitanand, N. N.; Riabov, V.; Samsonov, V.; Taranenko, A.; Рябов, Виктор Германович; Тараненко, Аркадий ВладимировичThe PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section, mean transverse momentum, mean transverse momentum squared of inclusive J/psi, and cross section ratio of psi(2S) to J/psi at forward rapidity in p + p collisions at root s = 510 GeV via the dimuon decay channel. Comparison is made to inclusive J/psi cross sections measured at root s = 200 GeV and 2.76-13 TeV. The result is also compared to leading-order nonrelativistic QCD calculations coupled to a color-glass-condensate description of the low-x gluons in the proton at low transverse momentum (p(T)) and to next-to-leading order nonrelativistic QCD calculations for the rest of the p(T) range. These calculations overestimate the data at low p(T). While consistent with the data within uncertainties above approximate to 3 GeV/c, the calculations are systematically below the data. The total cross section times the branching ratio is BR d sigma(J/)(psi)(pp) / dy(1.2 < vertical bar y vertical bar < 2.2,0 < p(T) < 10 GeV/c) = 54.3 +/- 0.5(stat) +/- 5.5(syst) nb.
- ПубликацияТолько метаданныеMeasurement 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.
- ПубликацияТолько метаданныеNuclear modification factor and flow of charm and bottom quarks in Au plus Au collisions at root S-NN=200 GeV by the PHENIX Experiment(2019) Hachiya, T.; Adare, A.; Afanasiev, S.; Aidala, C.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий ВладимировичExperimental results at RHIC and at the LHC show a similar strong suppression for light and heavy quark probes at high P-T, and a possible quark mass dependence of suppression at low P-T. More high precision measurements of separated charm and bottom are needed to quantify the dependence of medium effects on the quark mass. The PHENIX experiment measured separated electrons from bottom and charm decays using displaced vertex distributions at mid-rapidity vertical bar y vertical bar <0.35. Azimuthal anisotropy of electrons from separated charm and bottom decays are obtained from high statistics Au+Au data taken in 2014. PHENIX also measures muons from heavy quark decays in d+Au collisions at forward rapidity to study collective effects on heavy flavor production in small systems. These proceedings report the azimuthal anisotropy of charm and bottom at mid-rapidity in minimum bias Au+Au collisions and the anisotropy of single muons from heavy quark decays in d+Au collisions.
- ПубликацияТолько метаданныеTransverse single-spin asymmetry of forward n mesons in p + p collisions at √s = 200 GeV(2026) Abdulameer, N. J.; Acharya, U.; Aidala, C.; Ajitanand, N. N.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
- ПубликацияТолько метаданныеFeasibility of Measurements of the Properties of Thermal Photons in Heavy-Ion Collisions at the NICA Accelerator(2022) Ivanishchev, D. A.; Kotov, D. O.; Kryshen, E. L.; Malaev, M. V.; Riabov, V. G.; Рябов, Виктор Германович© 2022, Pleiades Publishing, Ltd.Abstract: Thermal photons are a valuable source of information about the properties of hot and dense matter produced in relativistic heavy-ion collisions. The effective temperature measured at RHIC and LHC energies greatly exceeds the temperature of the expected phase transition to the state with deconfined quarks and gluons known as quark–gluon plasma (QGP). Measurements of direct photons in heavy-ion collisions at the NICA accelerator will enable assessment of the effective temperature of the emerging medium at lower energies and trace the transition from partonic to hadronic degrees of freedom. The feasibility of studying thermal photons in the MPD experiment at NICA in Au–Au collisions using the photon conversion method is analyzed.
- ПубликацияТолько метаданныеJet modification via π0 -hadron correlations in Au+Au collisions at SNN =200 GeV(2024) Abdulameer, N. J.; Acharya, U.; Adare, A.; Afanasiev, S.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович
- ПубликацияТолько метаданныеPHENIX measurements of low momentum direct photon radiation(2019) Khachatryan, V.; Adare, A.; Afanasiev, S.; Aidala, C.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий ВладимировичThe versatility of RHIC allowed the PHENIX collaboration to measure low momentum direct photons from small systems, such as p+p, p+A, d+Au at root s(NN) = 200 GeV as well as from large A+A systems, such as Au+Au and Cu+Cu at 200 GeV and Au+Au at 62.4 GeV and 39 GeV. In these measurements PHENIX has discovered a large excess over the scaled p+p yield of direct photons in A+A collisions, and a non-zero excess over the scaled p+p yield in central p+A collisions. Another PHENIX discovery is that at low-p(T) the integrated yield of direct photons, dN(gamma)/dy, from large systems follows a universal scaling as a function of the charged-particle multiplicity, (dN(ch)/d eta)(alpha), with alpha = 1.25. The observed scaling properties of direct photons from these systems show that the photon production yield increases faster than the charged-particle multiplicity.
- ПубликацияТолько метаданныеMeasurement 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 ВладимировичWe 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.
- ПубликацияТолько метаданныеTransverse single spin asymmetries of forward neutrons in p+p, p+Al, and p+Au collisions at sNN =200 GeV as a function of transverse and longitudinal momenta(2022) Acharya, U. A.; Aidala, C.; Akiba, Y.; Alfred, M.; Blau, D.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий Владимирович© 2022 authors. Published by the American Physical Society.In 2015 the PHENIX collaboration at the Relativistic Heavy Ion Collider recorded p+p, p+Al, and p+Au collision data at center of mass energies of sNN=200 GeV with the proton beam(s) transversely polarized. At very forward rapidities η>6.8 relative to the polarized proton beam, neutrons were detected either inclusively or in (anti)correlation with detector activity related to hard collisions. The resulting single spin asymmetries, that were previously reported, have now been extracted as a function of the transverse momentum of the neutron as well as its longitudinal momentum fraction xF. The explicit kinematic dependence, combined with the correlation information allows for a closer look at the interplay of different mechanisms suggested to describe these asymmetries, such as hadronic interactions or electromagnetic interactions in ultraperipheral collisions, UPC. Events that are correlated with a hard collision indeed display a mostly negative asymmetry that increases in magnitude as a function of transverse momentum with only little dependence on xF. In contrast, events that are not likely to have emerged from a hard collision display positive asymmetries for the nuclear collisions with a kinematic dependence that resembles that of a UPC based model. Because the UPC interaction depends strongly on the charge of the nucleus, those effects are very small for p+p collisions, moderate for p+Al collisions, and large for p+Au collisions.
- ПубликацияТолько метаданныеMeasurements of charm, bottom, and Drell-Yan via dimuons in p plus p and p plus Au collisions at root S-NN=200 GeV with PHENIX at RHIC(2019) Leung, Y. H.; Adare, A.; Afanasiev, S.; Aidala, C.; Blau, D. S.; Riabov, V.; Samsonov, V.; Taranenko, A.; Блау, Дмитрий Сергеевич; Рябов, Виктор Германович; Тараненко, Аркадий ВладимировичDilepton spectra are a classic probe to study ultra-relativistic heavy ion collisions. At RHIC energies, the dimuon continuum is dominated by correlated pairs from semi-leptonic decays of charm and bottom hadrons and the Drell-Yan process. The dimuon spectra contain information on heavy flavor angular correlations, which can constrain the relative contributions from different heavy flavor production mechanisms. Studying heavy flavor correlations in p+Au collisions may provide further insight on cold nuclear matter effects. Measurements of the Drell-Yan cross-section can provide constraints to PDFs, as well as further our understanding in initial state interactions in p+Au collisions. In this talk, we report measurements of pp pairs from charm, bottom, and Drell-Yan in p+p and p+Au collisions at root S-NN = 200 GeV. A further shape analysis is applied to the heavy flavor pair correlations to extract the relative contributions to heavy flavor production mechanisms.