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Брандин, Андрей Владимирович

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Брандин

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Андрей Владимирович

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Только метаданные
Observation of the Electromagnetic Field Effect via Charge-Dependent Directed Flow in Heavy-Ion Collisions at the Relativistic Heavy Ion Collider
(2024) Abdulhamid, M. I.; Aboona, B. E.; Adam, J.; Adams, J. R.; Alekseev, I.; Alpatov, E.; Brandin, A. V.; Kochenda, L.; Kraeva, A. Yu.; Kravtsov, P.; Okorokov, V. A.; Parfenov, P.; Povarov, A.; Strikhanov, M.; Taranenko, A.; Vasiliev, A. N.; Алексеев, Игорь Геннадьевич; Алпатов, Егор Вячеславович; Брандин, Андрей Владимирович; Краева, Анна Юрьевна; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Поваров, Алексей Сергеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович; Васильев, Александр Николаевич
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First Measurement of Lambda(c) Baryon Production in Au plus Au Collisions at root s(NN)=200 GeV
(2020) Adam, J.; Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
We report on the first measurement of the charmed baryon Lambda(+/-)(c) production at midrapidity (vertical bar y vertical bar < 1) in Au + Au collisions root s(NN) = 200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The A(c)/D-0 [denoting (Lambda(+)(c) + Lambda(-)(c))/(D-0 + (D) over bar (0))] yield ratio is measured to be 1.08 +/- 0.16 (stat) 0.26 (sys) in the 0%-20% most central Au + Au collisions for the transverse momentum (p(T)) range 3 < p(T) < 6 GeV/c. This is significantly larger than the PYTHIA model calculations for p + p collisions. The measured A(c)/D-0 ratio, as a function of p(T) and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au + Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured Lambda(c)/D-0 ratio.
Только метаданные
Long-range collectivity in small collision systems with two- and four-particle correlations at STAR
(2019) Huang, S. L.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
New STAR measurements of two- and four-particle (c(2){4}) azimuthal angle correlations are reported for p+Au collisions at 200 GeV and d+Au collisions from 19.6 to 200 GeV. A negative c(2){4), consistent with collective anisotropic flow, is observed in high multiplicity d+Au events at 62.4 and 200 GeV where the statistical significance of the data allows an analysis. A template fitting method, employed to subtract non-flow contributions to the two-particle correlations, allows the extraction of the anisotropy coefficients (v(2)) for these systems at their respective energies. The v(2) results for different energies show a common dependence on the charged particle multiplicity density << dN(ch)/d eta >>, which provide important insight on the nature of collective behavior in small collision systems.
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The STAR BES-II and Forward Rapidity Physics and Upgrades
(2019) Yang, Q.; Adam, J.; Adamczyk, L.; Adams, J. R.; Alekseev, I.; Brandin, A. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
The second phase of the Beam Energy Scan at RHIC, BES-II, is scheduled to start in 2019 and will explore the high baryon density region of the QCD phase diagram with precision measurements. The detector upgrades will enhance some of the key measurements by extending STAR's kinematic reach, like the kurtosis of net-protons distribution which could pinpoint the position of a critical point. The upgrades currently under way comprise: the replacement of the inner TPC sectors, the Event Plane Detector (EPD) and the end-cap TOR Building on these upgrades STAR is planning to further enhance its detector capabilities by installing a Forward Calorimeter System (FCS) integrating an electromagnetic and hadronic calorimeter and a Forward Tracking System (FTS) combining 3 Silicon mini-strip disks and 4 Small-Strip Thin Gap Chamber (sTGC) wheels. The forward upgrades are motivated by studying the initial state of nucleons and nuclei and the exploration of cold QCD physics in the very high and low x regions. This contribution will highlight these upgrades and some of the physics opportunities that they allow.
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Pattern of global spin alignment of ϕ and K*0 mesons in heavy-ion collisions
(2023) Abdallah, M. S.; Aboona, B. E.; Adam, J.; Adamczyk, L.; 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
Notwithstanding decades of progress since Yukawa first developed a description of the force between nucleons in terms of meson exchange1, a full understanding of the strong interaction remains a considerable challenge in modern science. One remaining difficulty arises from the non-perturbative nature of the strong force, which leads to the phenomenon of quark confinement at distances on the order of the size of the proton. Here we show that, in relativistic heavy-ion collisions, in which quarks and gluons are set free over an extended volume, two species of produced vector (spin-1) mesons, namely П• and K*0, emerge with a surprising pattern of global spin alignment. In particular, the global spin alignment for П• is unexpectedly large, whereas that for K*0 is consistent with zero. The observed spin-alignment pattern and magnitude for П• cannot be explained by conventional mechanisms, whereas a model with a connection to strong force fields2вЂ“6, that is, an effective proxy description within the standard model and quantum chromodynamics, accommodates the current data. This connection, if fully established, will open a potential new avenue for studying the behaviour of strong force fields. At the Relativistic Heavy Ion Collider, observations of two meson species produced by heavy-ion collisions, П• and K*0, show surprising patterns of global spin alignment, being unexpectedly large and consistent with zero, respectively.
Только метаданные
Search for the chiral magnetic effect through beam energy dependence of charge separation using event shape selection
(2026) Aboona, B. E.; Adam, J.; Agakishiev, G.; Aggarwal, I.; Alekseev, I.; Alpatov, E.; Brandin, A. V.; Kochenda, L.; Kraeva, A. Yu.; Kravtsov, P.; Okorokov, V. A.; Parfenov, P.; Povarov, A.; Strikhanov, M.; Taranenko, A.; Vasiliev, A. N.; Алексеев, Игорь Геннадьевич; Алпатов, Егор Вячеславович; Брандин, Андрей Владимирович; Краева, Анна Юрьевна; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Поваров, Алексей Сергеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович; Васильев, Александр Николаевич
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Cumulants and correlation functions of net-proton, proton, and antiproton multiplicity distributions in Au plus Au collisions at energies available 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
We report a systematic measurement of cumulants, C-n, for net-proton, proton, and antiproton multiplicity distributions, and correlation functions, kappa(n), for proton and antiproton multiplicity distributions up to the fourth order in Au+Au collisions at root s(NN) = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4, and 200 GeV. The C-n and kappa(n) are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, y, and transverse momentum, pT. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010-2017) at the BNL Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity (vertical bar y vertical bar < 0.5) and transverse momentum 0.4 < p(T) < 2.0 GeV/c, using the STAR detector at RHIC. We observe a nonmonotonic energy dependence (root s(NN) = 7.7-62.4 GeV) of the net-proton C-4/C-2 with the significance of 3.1 sigma for the 0-5% central Au+Au collisions. This is consistent with the expectations of critical fluctuations in a QCD-inspired model. Thermal and transport model calculations show a monotonic variation with root s(NN). For the multiparticle correlation functions, we observe significant negative values for a two-particle correlation function, kappa(2), of protons and antiprotons, which are mainly due to the effects of baryon number conservation. Furthermore, it is found that the four-particle correlation function, kappa(4), of protons plays a role in determining the energy dependence of proton C-4/C-1 below 19.6 GeV, which cannot be understood by the effect of baryon number conservation.
Только метаданные
Beam energy dependence of net-Lambda fluctuations measured by the STAR experiment at the BNL Relativistic Heavy Ion Collider
(2020) Adam, J.; Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Alekseev, I.; Brandin, A. V.; Khyzhniak, Y. V.; Kochenda, L.; Kravtsov, P.; Nigmatkulov, G.; Okorokov, V. A.; Strikhanov, M.; Taranenko, A.; Алексеев, Игорь Геннадьевич; Брандин, Андрей Владимирович; Нигматкулов, Григорий Александрович; Окороков, Виталий Алексеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
The measurements of particle multiplicity distributions have generated considerable interest in understanding the fluctuations of conserved quantum numbers in the quantum chromodynamics (QCD) hadronization regime, in particular near a possible critical point and near the chemical freeze-out. Net-protons and net-kaons have been used as proxies for the net-baryon number and net-strangeness, respectively. We report the measurement of efficiency- and centrality-bin width-corrected cumulant ratios (C-2/C-1,C-3/C-3) of net-A distributions, in the context of both strangeness and baryon number conservation, as a function of collision energy, centrality, and rapidity. The results are for Au + Au collisions at five beam energies (root s(NN) = 19.6, 27, 39, 62.4, and 200 GeV) recorded with the Solenoidal Tracker at RHIC (STAR). We compare our results to the Poisson and negative binomial (NBD) expectations, as well as to ultrarelativistic quantum molecular dynamics (UrQMD) and hadron resonance gas (HRG) model predictions. Both NBD and Poisson baselines agree with data within the statistical and systematic uncertainties. UrQMD describes the measured net-A C-1 and C-3 at 200 GeV reasonably well but deviates from C-2, and the deviation increases as a function of collision energy. The ratios of the measured cumulants show no features of critical fluctuations. The chemical freeze-out temperatures extracted from a recent HRG calculation, which was successfully used to describe the net-proton, net-kaon, and net-charge data, indicate A freeze-out conditions similar to those of kaons. However, large deviations are found when comparing with temperatures obtained from net-proton fluctuations. The net-A cumulants show a weak but finite dependence on the rapidity coverage in the acceptance of the detector, which can be attributed to quantum number conservation.
Только метаданные
Measurements of multiplicity fluctuations of identified hadrons in inelastic proton–proton interactions at the CERN Super Proton Synchrotron: NA61/SHINE Collaboration
(2021) Acharya, A.; Adhikary, H.; Aduszkiewicz, A.; Allison, K. K.; Brandin, A.; Golosov, O.; Kargin, N.; Kashirin, E.; Morozov, S.; Selyuzhenkov, I.; Strikhanov, M.; Taranenko, A.; Брандин, Андрей Владимирович; Голосов, Олег Владимирович; Каргин, Николай Иванович; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович
© 2021, The Author(s).Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158 Ge/c beam momentum are presented. Three different measures of multiplicity fluctuations are used: the scaled variance ω and strongly intensive measures Σ and Δ. These fluctuation measures involve second and first moments of joint multiplicity distributions. Data analysis is preformed using the Identity method which corrects for incomplete particle identification. Strongly intensive quantities are calculated in order to allow for a direct comparison to corresponding results on nucleus–nucleus collisions. The results for different hadron types are shown as a function of collision energy. A comparison with predictions of string-resonance Monte-Carlo models: Epos, Smash and Venus, is also presented.
Открытый доступ
Hyperon global polarization in isobar Ru+Ru and Zr+Zr collisions at sNN=200GeV
(2025) Aboona, B. E.; Adam, J.; Agakishiev, G.; Aggarwal, I.; Alekseev, I.; Alpatov, E.; Brandin, A. V.; Kochenda, L.; Kraeva, A. Yu.; Kravtsov, P.; Okorokov, V. A.; Parfenov, P.; Povarov, A.; Strikhanov, M.; Taranenko, A.; Vasiliev, A. N.; Алексеев, Игорь Геннадьевич; Алпатов, Егор Вячеславович; Брандин, Андрей Владимирович; Краева, Анна Юрьевна; Окороков, Виталий Алексеевич; Парфенов, Петр Евгеньевич; Поваров, Алексей Сергеевич; Стриханов, Михаил Николаевич; Тараненко, Аркадий Владимирович; Васильев, Александр Николаевич