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Парфенов, Петр Евгеньевич

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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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Парфенов

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Петр Евгеньевич

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Теперь показываю 1 - 10 из 43

Только метаданные
Global Lambda-hyperon polarization in Au plus Au collisions at root S-NN=3 GeV
(2021) Abdallah, M. S.; Aboona, B. E.; Adam, J.; Adamczyk, L.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
Global hyperon polarization, (P) over barH, in Au + Au collisions over a large range of collision energy, root S-NN, was recently measured and successfully reproduced by hydrodynamic and transport models with intense fluid vorticity of the quark-gluon plasma. While naive extrapolation of data trends suggests a large (P) over barH as the collision energy is reduced, the behavior of (P) over barH at small root S-NN < 7.7 GeV is unknown. Operating the STAR experiment in fixed-target mode, we measured the polarization of Lambda hyperons along the direction of global angular momentum in Au + Au collisions at root S-NN = 3 GeV. The observation of substantial polarization of 4.91 +/- 0.81(stat.) +/- 0.15(syst.)% in these collisions may require a reexamination of the viscosity of any fluid created in the collision, of the thermalization timescale of rotational modes, and of hadronic mechanisms to produce global polarization.
Только метаданные
Measurement of the Sixth-Order Cumulant of Net-Proton Multiplicity Distributions in Au plus Au Collisions at root S-NN=27, 54.4, and 200 GeV at RHIC
(2021) Abdallah, M. S.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
According to first-principle lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region mu(B) <= T-c. In this range the ratio, C-6/C-2, of net-baryon distributions are predicted to be negative. In this Letter, we report the first measurement of the midrapidity net-proton C-6/C-2 from 27, 54.4, and 200 GeV Au + Au collisions at the Relativistic Heavy Ion Collider (RHIC). The dependence on collision centrality and kinematic acceptance in (p(T) , y) are analyzed. While for 27 and 54.4 GeV collisions the C-6/C-2 values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the C-6/C-2 ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high-energy nuclear collisions at top RHIC energy.
Только метаданные
Invariant jet mass measurements in pp collisions at s =200 GeV at RHIC
(2021) Abdallah, M. S.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
© 2021 authors. Published by the American Physical Society. Funded by SCOAP3.We present the first inclusive measurements of the invariant and softdrop jet mass in proton-proton collisions at s=200 GeV at STAR. The measurements are fully corrected for detector effects, and reported differentially in both the jet transverse momentum and jet radius parameter. We compare the measurements to established leading-order Monte Carlo event generators and find that STAR-tuned pythia-6 reproduces the data, while LHC tunes of pythia-8 and herwig-7 do not agree with the data, providing further constraints on parameter tuning. Finally, we observe that softdrop grooming, for which the contribution of wide-angle nonperturbative radiation is suppressed, shifts the jet mass distributions into closer agreement with the partonic jet mass as determined by both pythia-8 and a next-to-leading-logarithmic accuracy perturbative QCD calculation. These measurements complement recent LHC measurements in a different kinematic region, as well as establish a baseline for future jet mass measurements in heavy-ion collisions at RHIC.
Только метаданные
Flow and interferometry results from Au+Au collisions at sNN =4.5 GeV
(2021) Abdallah, M. S.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
©2021 American Physical Society.The beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) was extended to energies below sNN=7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Tracker At RHIC) experiment. In this mode, ions circulate in one ring of the collider and interact with a stationary target at the entrance of the STAR time projection chamber. The first results for Au+Au collisions at sNN=4.5 GeV are presented, demonstrating good performance of all the relevant detector subsystems in fixed-target mode. Results presented here include directed and elliptic flow of identified hadrons, and radii from pion femtoscopy. The latter, together with recent HADES results, reveal a long-sought peak structure that may be caused by the system evolving through a first-order phase transition from quark-gluon plasma to the hadronic phase. Directed and elliptic flow for pions are presented for the first time at this beam energy. Pion and proton elliptic flow show behavior which hints at constituent quark scaling, and demonstrate that a definitive conclusion will be achievable using the full statistics of the ongoing second phase of BES (BES-II). In particular, BES-II to date has recorded fixed-target data sets with two orders of magnitude more events at each of nine energies between sNN=3.0 and 7.7 GeV.
Только метаданные
Azimuthal anisotropy measurements of strange and multistrange hadrons in U+ U collisions at sNN =193 GeV at the BNL Relativistic Heavy Ion Collider
(2021) Abdallah, M. S.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
© 2021 American Physical Society.We present systematic measurements of azimuthal anisotropy for strange and multistrange hadrons (Ks0, Λ, Ξ, and ω) and φ mesons at midrapidity (|y|< 1.0) in collisions of U+U nuclei at sNN=193 GeV, recorded by the STAR detector at the Relativistic Heavy Ion Collider. Transverse momentum (pT) dependence of flow coefficients (v2, v3, and v4) is presented for minimum bias collisions and three different centrality intervals. Number of constituent quark scaling of the measured flow coefficients in U+U collisions is discussed. We also present the ratio of vn scaled by the participant eccentricity (ɛn2) to explore system size dependence and collectivity in U+U collisions. The magnitude of v2/ɛ2 is found to be smaller in U+U collisions than that in central Au+Au collisions contradicting naive eccentricity scaling. Furthermore, the ratios between various flow harmonics (v3/v23/2, v4/v24/2) are studied and compared with hydrodynamic and transport model calculations.
Только метаданные
Projections of two-particle correlations onto transverse rapidity in Au+Au collisions at sNN =200 GeV at STAR
(2022) Alekseev I.; Brandin A. V.; Kochenda L.; Kravtsov P.; Nigmatkulov G.; Okorokov V. A.; Parfenov P.; Strikhanov M.; Taranenko A.; Vasiliev A. N.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович; Васильев, Александр Николаевич
Two-particle correlation measurements projected onto two-dimensional, transverse rapidity coordinates (yT1,yT2) provide an independent, orthogonal view of the multidimensional correlation distribution that is most often studied via angular projections. As such, these independent transverse projections allow access to manifestations of dynamical fluctuations in relativistic heavy-ion collisions that angular-correlation measurements may not be sensitive to. We report nonidentified charged-particle correlations for Au+Au minimum-bias collisions at sNN=200 GeV taken by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Correlations are presented as two-dimensional functions of transverse rapidity for like-sign, unlike-sign, and all charged-particle pairs, as well as for particle pairs whose relative azimuthal angles lie on the near-side, the away-side, or at all relative azimuth. The correlations are constructed using charged particles with transverse momentum pT≥0.15 GeV/c, pseudorapidity from -1 to 1, and azimuthal angles from -π to π. The significant correlation structures that are observed evolve smoothly with collision centrality. The major correlation features include a saddle shape plus a broad peak with maximum near yT≈3, corresponding to pT≈1.5 GeV/c. The broad peak is observed in both like- and unlike-sign charge combinations and in near- and away-side relative azimuthal angles. The all-charge, all-azimuth correlation measurements are compared with the predictions of hijing and epos to provide theoretical context for these new measurements. The results indicate that the correlations for peripheral to mid-central collisions can be approximately described as a superposition of nucleon + nucleon collisions with minimal effects from the quantum chromodynamics medium. Strong medium effects are indicated in mid- to most-central collisions. © 2022 American Physical Society.
Только метаданные
Measurements of H Λ3 and H Λ4 Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region
(2022) Abdallah, M. S.; Aboona, B. E.; Adam, J.; Alekseev, I.; Brandin A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Parfenov, P.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
Только метаданные
Centrality and transverse-momentum dependence of higher-order flow harmonics of identified hadrons in Au+Au collisions at sNN =200 GeV
(2022) Alekseev I.; Brandin A. V.; Khyzhniak E.; Kochenda L.; Kravtsov P.; Nigmatkulov G.; Okorokov V. A.; Parfenov P.; Strikhanov M.; Taranenko A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
We present high-precision measurements of elliptic, triangular, and quadrangular flow v2, v3, and v4, respectively, at midrapidity for identified hadrons π, p, K, φ, Ks, Λ as a function of centrality and transverse momentum in Au+Au collisions at the center-of-mass energy sNN=200 GeV. We observe similar vn trends between light and strange mesons which indicates that the heavier strange quarks flow as strongly as the lighter up and down quarks. The number-of-constituent-quark scaling for v2, v3, and v4 is found to hold within statistical uncertainty for 0-10%, 10-40%, and 40-80% collision centrality intervals. The results are compared to several viscous hydrodynamic calculations with varying initial conditions, and could serve as an additional constraint to the development of hydrodynamic models. © 2022 American Physical Society.
Только метаданные
Pair invariant mass to isolate background in the search for the chiral magnetic effect in Au + Au collisions at sNN =200 GeV
(2022) Alekseev I.; Brandin A. V.; Khyzhniak E.; Kochenda L.; Kravtsov P.; Nigmatkulov G.; Okorokov V. A.; Parfenov P.; Strikhanov M.; Taranenko A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
Только метаданные
Evidence for Nonlinear Gluon Effects in QCD and Their Mass Number Dependence at STAR
(2022) Alekseev I.; Brandin A. V.; Khyzhniak E.; Kochenda L.; Kravtsov P.; Nigmatkulov G.; Okorokov V. A.; Parfenov P.; Strikhanov M.; Taranenko A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π0s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π0 pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale Qs2 on the mass number A. A linear scaling of the suppression with A1/3 is observed with a slope of -0.09±0.01. © 2022 American Physical Society.