The main objective of the Multi-Purpose Detector (MPD) at NICA is to study the structure of the QCD phase diagram at finite temperatures and high baryochemical potentials. To reach this goal, the MPD will study heavy-ion collisions in a wide energy range 2.4-11 GeV. By measuring a wide range of signals from heavy-ion collisions, the MPD will investigate various physics phenomena, including the...
Zavertyaev M. , on behalf of the BM@N Collaboration
The BM@N experiment is the first fixed-target experiment operated at
NICA accelerating complex, JINR, Dubna.
The BM@N experiment collected data on carbon, argon and xenon beams
with different solid targets within the energy range $\sqrt{s_{NN}} = 2.3-3.5GeV$.
Review of first physics results on pion, proton, deuteron,...
Hyperons created in non-central nucleus-nucleus collisions possess collective behavior known as elliptic flow (v2). Also, hyperons are sensitive to the magnetic field and vorticity of the produced system resulting in their polarization. The measurement of elliptic flow and the polarization of Lambda and Xi hyperons in Pb--Pb collisions, performed with the ALICE detector at the LHC are...
Understanding the internal structure of hadrons beyond the leading-twist approximation is essential for probing the non-perturbative dynamics of QCD. While high-$Q^2$ processes are dominated by gluon and sea quark dynamics, the low-$Q^2$ region requires non-perturbative modeling to capture the role of valence quarks and confinement. To address this, I investigate a wide range of distribution...
The enhancement of strangeness production has long been considered as a signature of quark–gluon plasma (QGP) formation in heavy-ion collisions. While extensive measurements have refined this idea over time, $\Sigma$ hyperons remain experimentally unexplored at the LHC energies. In this study, we present the first measurements of the transverse momentum ($p_{\mathrm{T}}$) spectra and...
It has been shown in the framework of effective models that QCD phase diagram as in thee color case as well as in two color one possesses dualities.
It means that various phenomena are dual with respect to each other. Then dualities were shown in a more and more general setings. And then finally dualities has been shown from first principles,
three dualities as in two color QCD and one in...
The main goal in investigation of vector mesons production in
ultra-peripherall collisions (UPC) of relativistic ions is the possibility to constrain the nuclear and proton gluon distributions.
The strong electromagnetic fields accompanying heavy ions accelerated
at BNL or LHC may lead to huge vector mesons photoproduction in
ultra-peripheral collisions, where there is no overlap...
We study the effect of finite spin quark density on the chiral and deconfinement thermal crossovers using numerical simulations of lattice QCD with two dynamical light quarks. The finite spin density is introduced by the quark spin potential in the canonical formulation of the spin operator. We show that both chiral and deconfinement temperatures are decreasing functions of the spin potential....
D mesons and the λ baryon are currently considered as one of the most perspective probes for search of quark de-confinement of the matter during its transition from a state of hadron gas to quark-gluon plasma. The tracking system of the MPD experiment at NICA collider will include the vertex silicon detector MPD-ITS designed for the efficient registration of these short-lived products of...
The hadronic light-by-light (HLbL) contribution to the muon anomalous magnetic moment is calculated within a nonlocal quark model incorporating scalar--pseudoscalar and vector--axial-vector interactions.
Both resonance contributions and contact terms are included in the calculation.
For the non-strange quark loop, the obtained contribution is
$
a_{\mu}^{\mathrm{HLbL,\,Loop}} = (93 \pm...
Studies of the phase diagram of strongly interacting matter created in nuclear collisions are typically carried out using event-by-event fluctuations. The strongly intensive quantities form a family of promising observables that are free from trivial volume fluctuations. In the case of multiplicity fluctuations over separate rapidity intervals, the behavior of the corresponding strongly...
In the collisions of heavy ions at the beam energy of 3.8A GeV dense baryonic matter is produced within the overlap region of colliding nuclei. The azimuthal anisotropy of produced in the collision particles is a sensitive probe of the properties of the dense baryonic environment. We present the preliminary results for the first coefficient of the Fourier decomposition of azimuthal...
The effect of nuclear medium on proton-nucleus scattering amplitude is investigated by analyzing experimental differential cross sections of proton elastic scattering on $^{90}$Zr at a very wide range of incident energies from 12.7 to 1000 MeV using the microscopic model of proton–nucleus optical potential. This effect has a major impact on the proton-nucleon cross section, σ, the most...
SU(2) QCD have previously been extensively studied and it was found, that qualitatively it possesses similar properties to it's real version with SU(3) color gauge group. Some of those properties, confinement-deconfinement transition and chiral symmetry restoration, are of a great interest. Thus, studying it's properties may help in understanding those of a real QCD. In addition, SU(2) QCD has...
We investigate the transverse momentum spectra and entropy per unit rapidity of charged pions produced in central Au--Au collisions at $\sqrt{s_{NN}} = 7.7$ and $11.5$~GeV, relevant for the NICA energy domain. The low-$p_T$ region is fitted using a Tsallis distribution, while the intermediate-to-high $p_T$ tail is described by a hadron resonance gas (HRG) model incorporating resonance decay...
Direct photons produced in electromagnetic processes in heavy ion collisions do not interact with other particles in the collision zone. Analysis of direct photon spectra and anisotropic flow could provide additional information on the conditions at the production time and on the development of collective flow. Spectra and flow of direct photons are quantified based on the corresponding...
Within Yang-Mills-Proca theory with external sources, regular, finite energy solutions are obtained. It is shown that color electric/magnetic fields have two components: the first part is a gradient/curl component,
respectively, and the second part is a nonlinear component. It is shown that the color electric field has an Y-like spatial distribution.
Such an Y-like behavior arises because...
Recent results on short-lived hadronic resonances obtained with the ALICE at LHC energies are presented.
These results include masses, widths, transverse momentum spectra,
yields and the ratios of resonance yields to those of longer-lived particles, and elliptic flows.
Results will be compared with model predictions and measurements at lower energies.
A key goal of beam energy scan programs with relativistic heavy-ion collisions at √sNN=2-5 GeV is probing the high-density equation of state (EoS) and possible phase transitions in dense baryonic matter. Anisotropic flow measurements provide critical insights into these properties through the final-state charged-particle azimuthal distributions. However, for the MPD experiment at NICA...
In the framework of explicitly covariant formulation of the light-front dynamics, we calculate the relativistic He-3 wave function. It is determined by 32 spin-isospin components, each of them depends on five variables. As interaction, we take the one-meson exchange kernel as it is, without any potential approximation. At the non-relativistic relative momenta, five of these components dominate...
Reanalysis of the relatively old data collected by the CERES/NA45 experiment at the CERN SPS in 0–30% central PbAu collisions at $\sqrt{s_{NN}}$ = 17.3 GeV has been performed. For the first time, the measurement of the $v^{1/3}_{3}/v^{1/2}_{2}$ ratio reveals, independently of the hydrodynamic models, hydrodynamic behavior of the formed system. Recently, the CMS data have revealed long-range...
After the short introductions of the experimental findings of $d^*(2380)(D_{03})$ [1,2,3] and of several theoretical efforts to interpret its structure, the study of $d^*(2380)$ on the quark–gluon degrees of freedom is presented in this talk. Based on our SU(3) chiral constituent quark model, its mass, width, wave function, and partial widths of almost all possible strong decays are evaluated...
The Relativistic Heavy Ion Collider (RHIC), located at Brookhaven National Laboratory,
is celebrating its 25th year of operation, making a significant contribution in nuclear physics research.
Over the past 25 years, RHIC has been instrumental in studying fundamental aspects of matter by
colliding a variety of atomic nuclei, from protons to uranium, at different energies from 3 to 200...
Quark-gluon plasma created in heavy-ion collision experiments is subjected to rapid rotation which
might modify QCD properties. In this report we are going to present the results of lattice study
on how rotation influences phase transitions in gluodynamics and QCD.
To study rotation we pass to the reference frame which rotates with the system.
In this frame the problem is reduced to...
Exclusive photoproduction of heavy $J/\Psi$ meson is performed within the handbag
approach where amplitudes factorize into hard subprocesses and generalized parton
distributions (GPDs). The general parton distributions (GPDs) for gluons $H_g$, are
constructed using double distribution representation. The calculated cross section for
few sets of $H_g$, GPDs describe fine $J/\Psi$...
The aim of the work is to investigate the neutron induced reactions in a massive target for ADS as a function of neutron moderators, where MCNP6 transport code is used. The ADS (Accelerator Driven System) contains three main parts: 1). Target, where the proton beam delivers its energy, 2). Nuclear fuel and cooling system, 3). Accelerator. Irradiation of the target by a relativistic proton...
Quark (q) and gluon (g) jets have significantly different parameters. The normalized distribution of jets by the jet parameter can be measured. This distribution is equal to the sum of the normalized distributions of g- and q-jets (q/g-templates) with weights aG and (1-aG), respectively, where aG is the g-jet fraction in jet sample. Therefore, to measure q/g-templates, it is necessary to...
Abstract: In this paper we studied the behaveours of α_S (q^2) of π^- mesons and protons produced in π^- C interactions and pp interactions at two different incident energies. We note that in π^- C interactions are produced the secondary cumulative particles in difference from pp interactions.
In this paper we showed that with the help of the cumulative particles from π^- C interactions at 40...
We give a report on new developments in the ReneSANCe Monte Carlo event generator. ReneSANCe is an event generator for simulation of the Standard Model processes at $ee$, $pp$ and $\gamma\gamma$ colliders.
A track detector based on a liquid scintillator is being developed at JINR VBLHEP. Liquid xenon is supposed to be used as the active medium in the final version of the detector. The detector is a steel vessel with windows for registration scintillation flashes. Light registration is carried out by position-sensitive elements - SiPM matrices of 8x8 cells. The purpose of the detector being...
We investigate the running coupling constant $\alpha_s$($q^2$) for $\pi^-$-mesons and protons produced in $p+p$ and $p+C$ interaction at 10 GeV/c. The precise determination of $\alpha_s$($q^2$) critically depends on the choice of the cut-off parameter $\Lambda_{QCD}$ in its defining expression. For this analysis, we adopt $\Lambda_{QCD} = (c \hbar) GeV = 0.197 GeV$. The resulting...
In modern high-energy and elementary particle physics experiments, the proportion of silicon detector systems is growing. The world's leading experiments: ALICE, ATLAS, CMS at the Large Hadron Collider, STAR at the Relativistic Heavy Ion Collider (RHIC), MPD, SPD at the NICA collider currently use or plan to implement silicon pixel detectors as the basis of their tracking systems. These...
This paper is devoted to the study of the running coupling constant $\alpha_s$ ($q^2$ ) of $\pi^-$ meson and protons from p+p and p+C interactions at 4.2 GeV/c. It is well known fact that the more correct value of the cut parameter $\Lambda_{QCD}$ in the formula of $\alpha_s$ ($q^2$ ) plays very important role in the obtaining the right values of the strong coupling constant $\alpha_s$ ($q^2$...
The relativistic quantum-mechanical description of a charged Laguerre-Gauss beam accelerated in a uniform electric field has been fulfilled [1]. Stationary wave eigenfunctions are rigorously derived. The evolution of the beam parameters during acceleration is considered in detail. The practically important effect of extraordinary suppression of transverse spreading of the beam is discovered,...
In this report we present the results of our study of rotating gluodynamics. In particular, we carry out lattice calculation of total angular momentum of rotating gluodynamics for various temperatures and angular velocities within local thermalization approximation. In this approximation, instead of simulating the full action, we use the action with the coefficients being fixed at some...
After the discovery of the Higgs boson in the LHC experiments, measurements of its properties began. The measured mass of the Higgs boson is 125 GeV. At this mass, the probability of its decay into bb is about 58%, which means that more than half of the produced Higgs bosons decay into a pair of bb quarks. Therefore, this channel is very important for studying the properties of the Higgs...
This report presents an overview of the latest results and research methodology of the search for Higgs boson decay into Dark Matter (DM) particles, using data obtained at first (√𝑠 = 7 TeV, 8 TeV ) and second (√𝑠 = 13 TeV ) Large Hadron Collider (LCH) Runs, corresponding to a luminosity of 4.9 - 19.7 and 139 - 140 fnb-1, respectively. Results were interpreted in the context of models where...
We study spin-flavor oscillations of neutrinos in a magnetic field within the quantum field theory approach in which neutrinos are virtual particles. Neutrinos are taken to be Majorana particles having a nonzero transition magnetic moment. We derive the dressed propagators of the neutrino mass eigenstates exactly accounting for the magnetic field contribution. The matrix element and the...
High-order net-proton cumulants and the event volume definition in A+A collisions at NICA energies.
G. Feofilov, St. Petersburg State University, St. Petersburg, RF
E-mail: g.feofilov@spbu.ru
Thermodynamic predictions [1] have indicated that the non-Gaussian fluctuations of the event-by-event observables, such as the net electric charge, the net strangeness and the net baryon...
The spin polarization of lambda hyperons exhibits an anisotropic alignment with the total orbital angular momentum of the collision system, serving as a probe for vorticity in the strongly-interacting matter. We study the lambda hyperon decay into a proton and a pion to measure global polarization in heavy-ion collisions, adopting an approach previously used by the STAR Collaboration to...
While elliptic flow ($v_2$) is a well-established signature of the quark-gluon plasma (QGP) in heavy-ion collisions, its observation in small collision systems remains a topic of active investigation. The LHC experiments first demonstrated the existence of $v_2$ in most central high-multiplicity collisions of p+p/Pb, which was soon complemented by the observation of collective effects in d+Au...
In the framework of field or quantum theory of the electromagnetism, presented by the Maxwell-Schrodinger and the Maxwell-Dirac equations, there is no an operator of the electric charge that could replace the artificial operation of charge conjugation and explain on the fundamental field-theoretical level a reason of the existence in the Nature the positive and negative...
The study of heavy-ion collisions with intermediate energies is a key direction of the future experimental program at the NICA accelerator complex. Within the scope of the collider commissioning activities, the installation of Beam-Beam Counter (BBC) prototype (Phase 0) is planned at the SPD interaction point. To determine the preliminary operation conditions for the detector, the simulation...
author: Mikhail Tokarev
co-author: Imrich Zborovsky
Mikhail Tokarev$^{1 \natural}$ and Imrich Zborovsky$^{2 \flat}$
$^1$Joint Institute for Nuclear Research, Dubna, Russian
$^2$The Czech Academy of Science, Nuclear Physics Institute, Rez, Czech Republic
$^{\natural}$ E-mail: tokarev@jinr.ru
$^{\flat}$ E-mail: imrichzborovsky@gmail.com
Selection of cumulative...
The isospin violation in the strong decays of the spin-2 exotic charmonium-like state $X_2(4014)$ into channels $\omega J/\Psi$ and $\rho^0 J/\Psi$ has been studied within the framework of the covariant confined quark model, designed to eliminate any UV divergences in quark loops. We have interpreted the exotic hadron $X_2$ as a four-quark state with a $D^*\bar{D}^*$ molecular-type...
Modern experiments in physics are impossible without computer
simulations. The NICA MPD experiment also includes this stage.
The key element for accurate simulation is a detailed detector geometry. Geometry for physical modeling must contain information not only about the physical dimensions and materials of individual elements, but also information about the volumes formed in the detector....
Manifestation of nuclear effects in fractal analysis of Monte Carlo AMPT events using SePaC method
T.G. Dedovich$^{1,2}$ and M.V. Tokarev$^{1,2}$
$^1$Joint Institute for Nuclear Research, Dubna, Russia
$^2$Dubna State University, Dubna, Russia
E-mail: tdedovich@jinr.ru
Search for extreme directions associated with changes in the state of matter is one of the tasks of modern...
Nuclear states, beginning with the six-quark Fock component of the deuteron, cannot be described solely in terms of conventional nucleon, meson, and isobar degrees of freedom in view of the presence of hidden-color states in any color-singlet multi-quark system. The momentum distribution of quarks in a nucleus is not a simple superposition of their distributions within nucleons. The EMC...
An experimental study of xenon–cesium iodide interactions at a kinetic energy of 3.8 AGeV was conducted during the first physics run of the BM@N experiment. The BM@N setup incorporates forward detectors: the Forward Hadron Calorimeter (FHCal) and the Forward Quartz Cherenkov Hodoscope (FQH), which are employed to determine the geometry of nuclear collisions. This work presents a comparison of...
The charge asymmetry in the process $e^+e^-\to\pi^+\pi^-\pi^0\gamma$ is studied taking into account a longitudinal polarization of electrons (positrons) for photons with energies $\omega_\gamma\ll\sqrt{s}$. The asymmetry arises due to interference of amplitudes corresponding to production of pions in states with charge parity odd and charge parity even. One of the contributions to the charge...
Using event generators, simulations were performed of the production of particles with large transverse momenta in the central region of energies at the NICA collider. A large set of statistics was required to study the behavior of the inclusive cross section of rare processes, which include the production of particles near the kinematic boundaries of pp and dd reactions. In this region, the...
The production of protons with a large transverse momentum in the central rapidity region at high energies due to the process of coherent coalescence (recombination) of quarks is considered. The inclusive cross section of proton production is studied near the kinematic boundary of pp and dd reactions. In this kinematic region, explicit asymptotic formulas are obtained for the inclusive cross...
The resonance peak observed by WASA@COSY in the total cross section of the reaction of two-pion production in the isoscalar channel of the reaction $pn\to d\pi^0\pi^0$ [1] at invariant mass 2380 MeV with the width of 70 MeV, is considered as one of the most realistic candidate to the dibaryon resonance [2]. The isospin of this resonance is I=0 and spin-parity $J^P=3^+$. A similar...
The Multi-Purpose Detector (MPD) at the NICA facility is designed to study heavy-ion collisions at $\sqrt{s_{NN}} = 4$–$11$ GeV, aiming to explore the baryon-rich region of the QCD phase diagram to investigate the possible existence of a first-order phase transition and a critical end-point. Dilepton measurements, particularly the invariant mass spectrum of dielectrons, serve as a key...
Production of particles in reactions on nuclear targets in the kinematical region forbidden in the case of free proton target, i.e. cumulative region, is still a challenge to theoretical models. That is because the simplest impulse approximation fails to provide large enough cross sections for large momentum cumulative particles, even when Fermi motion is taken into account. This led to...
Study of strange particle production in nuclear collisions is one
of the most important items of the physics program of the MPD experiment.
As previously demonstrated on simulated data, the detector will provide
good conditions for reconstruction of strange particles via their
weak decays to charged products in the collider mode of NICA operation.
In this work, it is shown that the...
Within the framework of the quark model and the hyperspherical coordinate method, we study the bound states of four heavy quarks (tetraquarks). In the hypercentral approximation, the Schrödinger equation is reduced to a one-dimensional equation after averaging over the hyperspherical angles. An analytical solution to this equation was obtained using the variational method, along with a...
Method for increasing the efficiency of registration of minimum ionizing particles by fast detector on microchannel plates.
F.F.Valiev, N.I.Kalinichenko, A.Kozhedub, N.A.Makarov, V.N.Popov, G.A.Feofilov
St. Petersburg State University
Fast detectors on the microchannel plates (MCPs) have high time characteristics (short pulses of ~2 ns at the base, with a front at < 800 ps). They...
The search for glueballs – colorless bound states of gluons – is one of the most important tasks within the modern QCD. While parameters of glueballs are predicted under a wide range of models, their experimental observation is extremely difficult due to the mixing with the conventional mesons. Glueballs are predicted to be abundantly produced in glue-rich processes, such as charmonia decays....
Algorithm for identification two neutrons in a 3D neutron detector is discussed. Time of flight and spatial criteria for separating one- and two-neutron events are proposed. The efficiency of the proposed criteria is estimated.
One of the important parts of the MPD experiment is the electromagnetic calorimeter ECal, which consists of 50 half-sectors, each containing 768 cells (towers) of different types and spatial orientations [1]. To test the calibration procedure on cosmic ray muons, the half-sector position was changed by rotating it around the central axis, which corresponded to its positions in the final...
Neutral and charged decay modes of the X17 boson observed in dCu collisions at a momentum of 3.8 GeV/c per nucleon
Kh.U. Abraamyan$^{1,2 *}$, Ch. Austin$^{3}$, M.I.
Baznat$^{4}$,
K.K.~Gudima$^{4}$,
M.A. Kozhin$^{1}$,
S.G. Reznikov$^{1}$, and A.S. Sorin$^{1,5}$
$^1$VBLHEP JINR, 141980 Dubna, Moscow region, Russia\
$^2$International Center for Advanced Studies, YSU, 0025, Yerevan,...
Collective flow measurements in relativistic heavy-ion collisions can provide key constraints on the properties of strongly-interacting matter and its Equation of State (EoS) in the high net-baryon density regime. Light nuclei, such as deuterons, are particularly valuable in this context: their v1 coefficients are sensitive to the early-stage pressure gradients, and help distinguish between...
Properties and applications of QED parton distribution and fragmentation functions are discussed. Optimization of the factorization scale choice is demonstrated for specific processes. A new factorization scheme is proposed for Drell-Yan processes in QED. Features of QED and QCD parton distribution functions are compared.
The initial variant of the nonperturbative kinetic theory (NPKT) in the vacuum quark-antiquark creation in the conditions of the ultrarelativistic heavy-ion collisions was represented in a simplified semiphenomenological form as the Abelian projection of QCD, where the U(1) gauge theory with the masses and color charges of the light quarks was used for primary investigation of some features of...
At the beginning of the 21st century, a new phase state of strongly interacting matter was established, known as the quark-gluon plasma (QGP) [1]. To study the formation of the QGP in collisions of heavy nuclei, the solution of a system of equations of relativistic hydrodynamics with a specific equation of state (EoS) is typically employed. In light of difficulties for non-zero baryonic...
The constant growth of energies in particle accelerators gives grounds to raise the question of studying few-nucleon atomic nuclei within the framework of the relativistic approach. The well-studied quantum mechanical formalisms of Faddeev [1] and Yakubovsky [2] are not suitable for this due to their non-relativistic nature.
In our recent work [3], we carried out a relativistic generalization...
Nuclear fragmentation first observed in photographic emulsions exposed to cosmic rays and is now studied with greater precision using nuclear track emulsion (NTE) irradiated by relativistic muons. This approach offers a unique way to investigate multi-fragmentation processes induced purely by electromagnetic interactions [1]. Within the BECQUEREL experiment [2], we examined μ-nucleus...
In the report, the off-shell electromagnetic pion form factors in the Bethe-Salpeter formalism are considered. The separable kernel of the first rank quark-antiquark interaction is used to solve the equation analytically. The half-off-shell pion form factors $F_1$ and $F_2$ , which are related to each other by the Ward-Takahashi identity, are calculated. The obtained off-shell form factors as...
We investigate the contribution of the 12-th order QED corrections to the anomalous magnetic moment $a_L$ of a lepton $L$ ($L=e,~\mu$ and $\tau$) from diagrams with insertions of the photon vacuum polarisation operator consisting solely of purely lepton loops. The approach is based on consistent applications of dispersion relations for the polarisation operator and the Mellin-Barnes integral...
A motivation for the baryon femtoscopy at the energy range of the experiment Baryonic Matter at the Nuclotron (BM@N) is discussed. The BM@M results on the proton-proton and proton-deuteron femtoscopy in the interactions of the argon beam of 3.2 AGeV kinetic energy with the C, Al, Cu, Sn, Pb targets are presented. The analysis procedure is described in detail. The dependence of the pp and pd...
We have demonstrated that the charge sum rules for the quark fragmentation functions hold including simultaneously the contributions of mesons and baryons providing the conservation of the strangeness, electric and baryon charges. We also obtained the expression for the isospin conservation. The results are compatible to Gell-Mann–Nishijima formulas for quarks and hadrons manifesting a new...
A scheme for searching for anomalous leptons using a
magnetic spectrometer based on drift chambers and an electromagnetic
calorimeter is considered. The design and characteristics of the detectors are given, as well as the results of tests in cosmic rays. An estimate of the masses of the presumed
particles is given.
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
In the BM@N collaboration experiment, double differential distributions of transverse momentum and rapidity of positively charged pions and kaons have...
The gluon dominance model is developed to describe multiparticle production of secondary particles at high energies in lepton and hadron interactions, including annihilation processes and heavy quarkonium decays. According to this model, the multiparticle process is divided into two stages. The first stage describes the development of a quark-gluon cascade as a Markov branching process in the...
The Baryonic Matter at Nuclotron (BM@N) experiment at the NICA accelerator complex is currently in its active phase, analyzing data collected from the first physics run, and preparing for future data taking.
One of the most important software components for event reconstruction in high-multiplicity environment of heavy-ion interactions is a track reconstruction package. At BM@N, it was...
In this study, we calculate the transverse momentum distributions of hadrons using two frameworks: the finite-volume blast-wave model under local equilibrium and the Tsallis-3 statistics model under global equilibrium. To implement the local equilibrium model, we analyzed the relativistic Planck and Ott transformations for thermodynamic quantities. The Planck transformations are derived from...
A Highly Granular time-of-flight Neutron Detector (HGND) is currently under development for use in the BM@N experiment to measure the yields and flow of neutrons with energies of 0.3–4 GeV [1]. The ratio of neutron to proton yields and the neutron-proton differential directed flow are sensitive to the contribution of symmetry energy to the equation of state of dense nuclear matter in Au-Au...
Open-charm production constitutes a stringent test of next-to-leading-order (NLO) perturbative QCD, because at the scale of charm quark $\mu \simeq m_c$ the strong coupling constant is already moderately small $\alpha_S \ll 1$. Single Parton Scattering (SPS) calculations alone fail to reproduce the measured DD-pair production. A realistic description may also include either gluon to...
To extend the capabilities of the fixed-target BM@N experiment (JINR, Dubna), the Highly Granular Neutron Detector (HGND) [1] has been developed. This detector will enable unique measurements of neutrons in the kinetic energy range of 0.3-4.0 GeV. The HGND comprises two arms, each consisting of 8 layers of plastic scintillator with copper absorber plates in between. Each scintillation layer is...
In the theory of the vacuum particle creation in strong fields (Sauter-Schwinger effect) a small number of exactly solvable models acts as benchmarks [1]. In this respect, the nonperturbative kinetic theory methods also hold a prominent place. The analysis performed below is restricted by a class of the quantum kinetic equations of the Vlasov type in the strong electric fields (e. g.,...
In relativistic heavy ion collisions, a dense hot matter called quark-gluon plasma (QGP) is formed [1]. Information about the properties of formed medium can be obtained from data on the energy loss of quarks and gluons (partons) with high transverse momenta $p_{T}≫Λ_{QCD}$ produced in hard parton-parton interactions [2]. The energy loss of partons in QGP leads to the jet quenching effect in...
The Highly Granular Neutron Detector (HGND) is designed for the BM@N experiment, aimed at investigating neutron emission in heavy ion collisions at beam energies of up to 4A GeV. The HGND allows the identification of neutrons and the reconstruction of their energies using time-of-flight method, which is crucial for analyzing neutron yields and azimuthal flow. Given the challenging energy range...
Understanding the properties of Quark-Gluon Matter (QGM) at high baryon densities is essential for mapping the QCD phase diagram, probing the equation of state of dense nuclear matter, and shedding light on the structure of neutron stars and the evolution of the early universe. At high baryon potential, theoretical calculations of QCD become sophisticated and unstable. Therefore, the study of...
The process of hadronization is usually seen as a universal process for all types of colliding particles and at all energies. A regular approach used in existing SoftQCD MC generators is to portray it as Lund quark-gluon string (QGS) fragmentation. However, results from both colliders and cosmic ray experiments indicate the need to transition to non-universal scheme of hadron production in...
Some predictions on D-meson production in soft proton+proton, 2H+2H and 4He+4He interactions at √S=10 and 20 GeV are given for future SPD/NICA experiment using Geant4 FTF model. Essential details of implementation of charmed particle production in the FTF model are considered. Results of model calculations of kinematical properties of the particles produced in hadron-hadron interactions in...
The Highly Granular Neutron Detector (HGND) is being developed for the BM@N (Baryonic Matter at Nuclotron) experiment on the extracted beam of the Nuclotron (JINR, Dubna). The HGND will be used to measure the neutron yields in energy range 300 – 4000 MeV as well as azimuthal asymmetry of neutron flow in nucleus-nucleus collisions at beam energies of 2–4 AGeV. At these energies, nuclear density...
Deviation of the cross section for the nuclear reaction X(a, b)Y from the Gamow formula due to an interaction additional to the Coulomb one in the entrance channel has been analyzed[1]. It is shown that the reaction cross section has an oscillating structure at low energies. If the maximum of the first oscillation is close to the threshold of the channel a+X, it has a resonance behavior[2]. To...
Two-particle femtoscopy via Bose–Einstein correlations (BEC) provides direct access to the space–time structure of particle-emitting sources in relativistic heavy-ion collisions. In this study, we present a systematic analysis of BEC for identical charged pion and kaon pairs in Au+Au collisions at Relativistic Heavy Ion Collider (RHIC) energies. Model calculations were performed using the...
A new silicon tracking station has been developed and implemented as part of the upgrade of the BM@N experiment’s tracking system at the Nuclotron, aimed at studying heavy-ion collisions. The station is based on CBM-BM@N–type double-sided silicon microstrip modules equipped with high-rate streaming readout electronics using STS-XYTER chips. Signal routing is realized via ultra-lightweight...
Supernova remnants and compact binary mergers are prime candidates for Galactic cosmic‑ray acceleration. We have evidence that HESS J1731-347 and GW170817 have the capacity to accelerate hadrons to TeV energies and could potentially harbor strange quark matter (SQM), thereby inspiring a quest for strangelets. A transition from the 2SC to CFL phase in quark matter could release strangelets...
A modern definition of New Physics is proposed.
A correction to the W-boson mass is calculated.
A modern definition of New Physics is proposed.
A correction to the W-boson mass is calculated.
A method for measurement of the fractal dimension for the blackbody derived.
Necessary conditions for existence of the bound states in extended quantum mechanics [1] obtained.
Complex, quaternion...
The Electromagnetic Calorimeter (ECal) is designed to measurement position, energy and time of flight of photons and electrons in heavy-ion collisions. This report presents the status of ECal testing for the Multi-Purpose Detector (MPD) at the NICA collider.
The dynamics of neutrinos in hot and dense magnetized stellar material, corresponding to magnetorotational supernova explosion, is considered. It is shown that taking into account fluctuations in the interaction of neutrinos with matter leads to the Fokker-Planck equation for the dynamics of the distribution function in the phase space. The component of the kinetic equation additional to the...
The Multi-Purpose Detector (MPD) experiment is a flagship heavy-ion experiment of the NICA facility at JINR, in Dubna expected to start operation in 2026. The experiment will operate in the energy range $\sqrt{s_{\rm NN}}$ = 4-11 GeV in collider mode and $\sqrt{s_{\rm NN}}$ = 2.4-3.5 GeV in fixed-target mode which covers the high net-baryon density region of the QCD phase diagram.
Particle...
The softening of the equation of state of the neutron star matter upon the inclusion of hyperons, leading to a reduction in their maximum mass below the limit established by observations, named "hyperon puzzle" remains one of unresolved problems in the nuclear astrophysics. This work investigates the structure of neutron stars within the Skyrme approach. In contrast to previous studies within...
This work discusses the current status of the Forward Hadron Calorimeter (FHCal) at MPD/NICA as its launch approaches. The main goal of FHCal is measurement of geometry of interaction by estimating of centrality and reaction plane orientation. Each arm of the FHCal will comprise 44 heterogeneous modules, and one of these arms has already been assembled in Dubna. A brief overview of the...
The research program of the SPD experiment at NICA facility is focused on studies of collisions of polarized protons and deuterons [1,2]. Studies of collisions of non-polarized light nuclei, 12C and 40Ca, are also considered as a possible extension of the SPD research program [3]. The SPD setup will be equipped with a pair of Zero Degree Calorimeters (ZDC) for luminosity measurements and...
In the year 1971 the pioneering works on fragmentation reactions in the collisions at relativistic energies began. At the same time in experiments at low energies deep- inelastic mechanism was discovered. To describe the fragmentation reactions at relativistic energies different models such as the EPAX and the Abrasion–Ablation models were developed. As the experiments on projectile...
An analysis of the geometric properties of rapidity space (Lobachevsky hyperbolic space) in multiple particle production is presented. Experimental data obtained using bubble chambers were analyzed using differential geometry methods. Bimodal angular distributions at nucleon interaction energies of 1.5–10 GeV were examined, indicating a transition from Euclidean to hyperbolic geometry starting...
A new generalization of the Multipomeron exchange model [1-4] for studying the multiparticle production in pp, pA and AA collisions is proposed, taking into account the effect of event-by-event string tension fluctuations [5]. It is shown that the new version of the model correctly reproduces the characteristic thermal behavior of $p_\rm{T}$ spectra in a wide energy range. Simultaneously, the...
An analysis of reconstructed $p_T$ spectra for light hadrons ($\pi^\pm$, $K^\pm$, $p$, $\bar{p}$) is presented for simulated Bi+Bi collisions at $\sqrt{s_{NN}} = 9.2$ GeV. The spectra are obtained with MPDRoot. The yield rapidity densities and meson yields are got. An improvement of low-$p_T$ energy loss correction is done.
The paper presents the results of calculations the formation of light neutron-rich nuclei, including 12He, on beams of short-lived nuclei produced at the NICA accelerator complex. The calculations are based on the reaction of double charge exchange in nuclear-nuclear interactions. The possibility of the neutron-rich nuclei formation on the booster-nuclotron accelerators are discussed. The...
The formation of weakly bound clusters in the hot, dense environment at midrapidity is among the intriguing phenomena observed in heavy-ion collisions.
Three main approaches have been proposed to describe cluster formation:
- Coalescence at kinetic freeze-out.
- Continuous formation via potential interactions between nucleons.
- Deuteron production through hadronic reactions.
We...
The phenomenon of multiple fragmentation of relativistic nuclei can serve as a source of coherent ensembles of the lightest nuclei and nucleons. In this respect only nuclear track emulsion providing 0.5 µm spatial resolution allow one to follow tracks of all relativistic fragments in forward cone defined by a nucleon Fermi motion [1]. The report will give a brief overview of the experimental...
Application of machine learning has become highly relevant for solving the problems of event reconstruction, particle identification, and impact parameter estimation [1, 2]. The present study focuses on the application of neural networks to predict the energy released in high-energy collisions of two gold nuclei (Au+Au) based on signals obtained from microchannel plate detectors. The initial...
A precision three-arm magnetic spectrometer SCAN-3 is being built for detecting charged (pi, K, p) and neutral (n) particles produced at the LHEP Nuclotron internal target in dA collisions. This project is aimed at studies of highly excited nuclear matter. The matter will be studied through observation of its particular decay products, that is, pairs of energetic particles with a wide opening...
Starting with the discovery of the nuclear component of cosmic rays, the nuclear track emulsion method (NTE) makes an opportunity to study the composition of the relativistic fragmentation of nuclei at high-energy accelerators. The promising potential of the relativistic approach to the analysis of ensembles of fragments was manifested in NTE exposed by nuclei at several GeV per nucleon...
NICA is a tool to investigate the early Universe in laboratory. It would be reasonable to recall some critical issues in physical cosmology development. GR was created by A. Einstein in 1915. In 1917 Einstein proposed the first (static) cosmological model. Soon after the A. Eddington proved that the model is unstable therefore it can not be realizable in nature. In 1922 and 1924 A. A....
The 8Be and 9B nuclei and a number of excitations of light isotopes near the binding thresholds constitute a whole class of unusually long-lived states at the lower limit of nuclear density and temperature. In the con-cepts of molecular-like or α-condensate structures, they are represented as associations of the lightest nuclei and nucleons separated in space. Identification of the known...
The report presents proposals for studying the interactions of relativistic nuclei in the space of four-dimensional velocities involving quarks and the formation of hadron jets. It is shown that in the energy range of the NICA collider, fractions of neighboring quarks can participate in the interaction of nuclei. In addition, the behavior of four-dimensional hadron jets is similar to that of...
For the first time in high energy physics, the final state of the reaction with the slow (missing) proton (that is at the region of so called Quasi-Free kinematics) was analyzed essentially in the framework of the 3-body Phase Space.
We present detailed analysis of the γd → πˉp p_S reaction at the initial energy range Eγ = 1.0-3.5 GeV, and missing slow proton momentum ps < 0.2 GeV/c....
In our discovered algebraic classification of n-dimensional Calabi-Yau spaces, we obtained an indication of the existence of exotic algebras and accompanying symmetries. To search for a possible primordial connection of such algebras and symmetries with number theory, we developed a theory of cyclic complex numbers and their non-Abelian extensions. Such theories are related to the cyclic...
