2025, Kuskov, V. A., Peresun’ko, D. Yu., Blau, D. S., Кусков, Владислав Андреевич, Пересунько, Дмитрий Юрьевич, Блау, Дмитрий Сергеевич

2023, Blau, D., Peresunko, D., Блау, Дмитрий Сергеевич, Пересунько, Дмитрий Юрьевич

Direct photons provide a possibility to test properties of hot matter created in proton-proton (pp), proton-nucleus (p-A) or nucleus-nucleus (A-A) collisions. As they are created in charged particles' scatterings and freely escape the hot region, they provide a tool to test all stages of the collision: the scattering of the partons of incoming nucleons, pre-equilibrium evolution and collective expansion of hot quark-gluon matter created in nucleus-nucleus collisions. Comparing direct photon production in pp, p-A and A-A collisions, one can check the scaling with the number of binary collisions expected at a high transverse momentum range and obtain insight into the hot and cold hadronic matter properties with soft photons. The collective elliptic flow of direct photons is a unique possibility to trace the collective flow formation and space-time evolution of the fireball. We review the experimental results on direct photon production in pp, p-A and A-A collisions at the Super Proton Synchroton (SPS), the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) energies and discuss an agreement of theoretical predictions with measurements. Finally, we present predictions of direct photon spectra and collective flow for lower energy collisions expected at the Nuclotron-based Ion Collider fAcility (NICA) and the Facility for Antiproton and Ion Research (FAIR).

2025, Golosov, O., Peresunko, D., Blau, D., Голосов, Олег Владимирович, Пересунько, Дмитрий Юрьевич, Блау, Дмитрий Сергеевич

2019, Acharya, S., Adamova, D., Adolfsson, J., Aggarwal, M. M., Belyaev, V., Bogdanov, A., Grigoriev, V., Ippolitov, M., Kaplin, V., Kondratyeva, N., Loginov, V., Melikyan, Y., Peresunko, D., Samsonov, V., Selyuzhenkov, I., Беляев, Владимир Никитич, Богданов, Алексей Александрович, Григорьев, Владислав Анатольевич, Ипполитов, Михаил Сергеевич, Кондратьева, Наталья Викторовна, Логинов, Виталий Александрович, Пересунько, Дмитрий Юрьевич

First results on K/pi, pi/pi and K/p fluctuations are obtained with the ALICE detector at the CERN LHC as a function of centrality in Pb-Pb collisions at v root s(NN) = 2.76 TeV. The observable nu(dyn), which is defined in terms of the moments of particle multiplicity distributions, is used to quantify the magnitude of dynamical fluctuations of relative particle yields and also provides insight into the correlation between particle pairs. This study is based on a novel experimental technique, called the Identity Method, which allows one to measure the moments of multiplicity distributions in case of incomplete particle identification. The results for p/pi show a change of sign in.dyn from positive to negative towards more peripheral collisions. For central collisions, the results follow the smooth trend of the data at lower energies and.dyn exhibits a change in sign for p/pi and K/p. nu(dyn)