In recent years, the PHENIX experiment has observed collectivity in small collision systems. This behavior resembles what is seen in large systems where quark-gluon plasma (QGP) is produced. However, whether QGP actually forms in small systems is still being debated.
This work presents measurements of the neutral pion elliptic flow ($v_2$) coefficients as a function of $p_T$ for different...
High-baryonic-density strongly interacting matter is created in collisions of heavy ions, and its properties can be probed through the azimuthal anisotropy of produced particle momenta. This anisotropy is commonly quantified via the Fourier coefficients of the particle azimuthal angle distribution. However, the measured coefficients are susceptible to significant biases introduced by the...
At the beginning of the 21st century, a new phase of strongly interacting matter,
known as the quark-gluon plasma (QGP), was established [1]. To study QGP formation in
heavy-ion collisions, the solution of system of relativistic hydrodynamics equations with
a specific equation of state (EoS) is typically employed. In light of difficulties for non-zero baryonic potentials within Lattice QCD,...
The MPD experiment will provide particle identification and broad coverage in transverse momentum and rapidity for neutral mesons decaying into photons, using different methodsbased on its electromagnetic calorimeter, tracking, and time-of-flight systems. The spectra and anisotropic flow of neutral mesons may help constrain the properties of the hot and dense nuclear matter created in...
Anisotropic flow serves as a sensitive probe of the equation of state (EOS) and transport properties of the strongly interacting matter. It is an important observable at intermediate beam energies, which current theoretical models associate with the high baryon density region of the QCD phase diagram. Despite extensive study, this region still requires additional experimental constraints. This...
The Multi-Purpose Detector (MPD) at NICA is primarily designed for collider experiments at $\sqrt{s_{NN}} = 4–11$ GeV. A recently proposed program of fixed-target experiments extends its research potential, allowing for the investigation of dense baryonic matter in ion collisions at lower center-of-mass energies $\sqrt{s_{NN}} = 2.4–3.5$ GeV. Running in the fixed-target mode requires a careful...
Due to quantum statistical effects and final-state interactions, momentum correlations between two or more particles emitted with small relative velocities (or, equivalently, small relative momenta in their center-of-mass system) provide a sensitive tool for probing the spatiotemporal characteristics of particle-production processes at femtometer scales (10^−15 m). Kaons are particularly...
Femtoscopic correlations of identical particles provide a powerful tool for probing the space-time structure and dynamical evolution of the particle-emitting source created in relativistic heavy-ion collisions. Measurements of femtoscopic radii constrain the characteristic homogeneity lengths of the expanding system and their dependence on collision geometry and particle momentum, thereby...
A.Zarchikov, G.A.Feofilov*
Saint-Petersburg University, St. Petersburg State University, SPbSU,
SPbU, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia.
*e-mail: g.feofilov@spbsu.ru
High-order cumulants of event-by-event multiplicity distributions are widely used in the search for the QCD critical point in relativistic heavy-ion collisions. Their sensitivity...
Higher-order multiplicity fluctuations can reveal features of particle production that are not accessible through variances and two-particle correlations alone. Their interpretation, however, is complicated by fluctuations in the number of particle-emitting sources. We develop a systematic construction of strongly intensive observables that remove this dependence within the independent-source...
The study of nuclear matter formed in relativistic heavy-ion collisions is one of the key tasks in high-energy physics. In addition to the quark-gluon plasma produced in such colliding systems, the hadron gas phase that represents the final stage of the collision is of particular interest. Investigation of resonance production in relativistic heavy-ion collisions serves as a primary tool for...
In 2025, data on $^{16}$O–$^{16}$O and $^{20}$Ne–$^{20}$Ne collisions were collected at the LHC for the first time. Unlike in the LHC runs with $^{208}$Pb beams conducted since 2010, a significant fraction of spectator fragments emitted in collisions of light isospin-symmetric nuclei, such as $^{16}$O and $^{20}$Ne, also have equal numbers of neutrons and protons. Consequently, these fragments...
Momentum distributions of light fragments produced in asymmetric fission in heavy ion collisions provide information on reaction dynamics and breakup mechanisms of spectator systems. At small emission angles relative to the beam direction and with high momentum resolution, energy spectra of light fragments exhibit a double-humped structure contrary to the Gaussian profile expected in usually...
A.T. D’yachenko$^{1,2}$
$^1$B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Center "Kurchatov Institute", Gatchina, Russia
$^2$Emperor Alexander I Petersburg State Transport University, St. Petersburg, Russia
Based on the effective Klein–Fock–Gordon equation [1], a description is given of the emission of cumulative protons, pions, and fragments (p, π, K, d, t)...
The Multi-Purpose Detector (MPD) at the NICA complex in Dubna is designed to investigate the strongly interacting matter in the vicinity of the QCD critical point. The properties of the medium created in heavy-ion collisions can be determined from the analysis of the hadron spectra. We present reconstructed invariant transverse-momentum spectra of the light hadrons ($\pi^\pm$, $K^\pm$, $p$)...
Hadron transverse momentum ($p_{T}$) spectra serve as a sensitive probe of matter produced in relativistic nuclear collisions, with statistical frameworks being widely used to extract its thermodynamic parameters. Despite extensive research into particle production across a wide range of collision energies, of particular interest is a detailed analysis of $p_{T}$ spectra under the conditions...
The search for extreme states associated with changes in the phase of nuclear matter is one of the key tasks of high-energy heavy-ion physics. It is known that systems exhibit fractal behavior near phase transitions. The fractality (intermittency) of identified charged hadrons in the pseudorapidity range |η| < 0.5 and the transverse momentum range 0.2 < pT < 2.0 GeV/c was studied in the STAR...
We present a comparison of Monte Carlo modified Glauber model predictions with recent measurements of the centrality dependence of total charged-particle yields in ¹⁶O+¹⁶O and ²⁰Ne+²⁰Ne collisions at the LHC. The model extends the Standard Glauber approach by introducing a single parameter, k, the mean fractional momentum loss per inelastic nucleon-nucleon collision due to multiparticle...
The Multi-Purpose Detector (MPD) experiment is a flagship heavy-ion experiment of the NICA facility at JINR, Dubna, currently under commissioning. The experiment will operate in the energy range $\sqrt{s_{NN}}$ = 4-11 GeV in collider mode and $\sqrt{s_{NN}}$ = 2.4-3.5 GeV in fixed-target mode, together covering the high net-baryon density region of the QCD phase diagram. Dielectron...
