Murad Badshah

We report a systematic generator-level study of identified-hadron production in minimum-bias Au+Au collisions at , 7, and 8 GeV using EPOS-LHC, EPOS-4, and SMASH. These frameworks represent different microscopic approaches, ranging from string/core-corona and hydrodynamic descriptions to purely hadronic transport. We compare rapidity distributions, transverse-momentum spectra, two-dimensional density maps, particle-yield ratios, and number-of-constituent-quark-scaled elliptic flow. Charged and neutral pions provide a relatively model-insensitive baseline dominated by bulk production and resonance feed-down, whereas , protons, and baryons exhibit stronger model dependence. The maps identify the longitudinal and transverse phase-space regions in which the model predictions diverge, although conclusions for rare strange particles are limited to statistically populated regions. Elliptic flow is presented as versus transverse kinetic energy per constituent quark, . All three models exhibit an approximately common trend at low and intermediate transverse kinetic energy, with the closest visual grouping in EPOS-LHC; deviations and statistical uncertainties increase at larger . Because each sample contains 50,000 events, no quantitative conclusions are drawn from sparsely populated forward-rapidity or high- regions. The results provide exploratory model baselines and identify strange-particle spectra, , , double-differential measurements, and identified-particle elliptic flow as priority observables in the NICA energy range.

Transverse-momentum ([Formula: see text]) spectra of identified hadrons are a powerful and precise phenomenological tool to study the collision-energy, centrality, and particle-species dependence of the matter created in relativistic heavy-ion collisions. We report a systematic study of [Formula: see text], [Formula: see text], p and [Formula: see text] production in Au[Formula: see text][Formula: see text][Formula: see text]Au collisions as a function of the RHIC Beam Energy Scan (BES) range of [Formula: see text]–62.4[Formula: see text]GeV. The component inverse-slope parameters (effective temperature-like) [Formula: see text] and [Formula: see text], the fractional contribution k, the weighted effective temperature-like parameter T, the mean transverse momentum [Formula: see text], the model-derived source-temperature parameter [Formula: see text], and the free normalization parameter [Formula: see text] are extracted and/or calculated within a two-component standard distribution, together with the fit-quality measure [Formula: see text]. The results are presented according to centrality, [Formula: see text] and [Formula: see text]. For the particle species available, T, [Formula: see text] and [Formula: see text] drop from central to peripheral collisions and rise with [Formula: see text], indicating systematic spectral softening towards the smaller collision systems. Saturation-like behavior is observed as a descriptive pattern in both the energy scan and the centrality scan: from an energy of about [Formula: see text][Formula: see text]GeV and upwards, the growth of T, [Formula: see text] and [Formula: see text] weakens, and the centrality interval, where the parameters are nearly saturated, moves towards more peripheral collisions as the energy of the collisions increases. The extracted parameters exhibit a clear mass ordering at fixed energy and centrality with proton/antiproton values larger than kaon values that in turn are larger than pion values. The contribution is the combined energy–centrality systematics of spectral hardness, rather than a new thermodynamic interpretation of the fitted parameters.

Multiplicity-differential transverse-momentum spectra of [ ], [ ], p, and [ ] produced in [ ] collisions at [ ], [ ], and [ ] TeV are analyzed in event-activity classes characterized by the mean charged-particle multiplicity [ ]. The spectra are fitted with two widely used phenomenological descriptions: (i) a thermodynamically consistent Tsallis form and (ii) a Hagedorn parametrization supplemented by an effective transverse-boost component. Both functions reproduce the measured [ ] distributions across energies and multiplicity bins with stable fit quality, with the largest deviations confined to the edges of the fitted ranges where acceptance effects and hard-scattering contributions are most influential. When presented versus [ ], the extracted parameters show clear and systematic trends. The effective temperature scales ([ ] in the Tsallis description and [ ] in the Hagedorn-based description) decrease with increasing event activity and exhibit mass ordering, while the high-[ ] tails harden with multiplicity: the Tsallis nonextensivity parameter q increases and the Hagedorn power index n decreases. Derived quantities such as [ ], [ ], [ ], [ ], and the characteristic momentum scales [ ] and [ ] provide compact measures of the soft-to-hard transition as event activity grows. The corresponding Hagedorn[ ]flow boost variables [ ], [ ], and [ ], together with tail-related exponents, furnish complementary characterizations of the effective transverse-boost and power-law behavior. The extracted transverse-boost parameter[ ] (and its related variables) increases mildly with [ ], indicating a stronger effective transverse expansion in higher-multiplicity events within the adopted parametrization. These multiplicity-and energy-resolved results provide a concise set of spectral parameters that can be used to benchmark phenomenological descriptions and to serve as quantitative constraints for event-generator descriptions of small-system particle production.

This study investigates the transverse momentum ( ) distributions of , , p ( ), , and Λ in various centrality classes of Pb-Pb collisions at TeV. The experimental spectra were analyzed using the Tsallis non-extensive distribution, from which the effective temperature ( T ), non-extensive parameter ( q ), and mean transverse momentum ( ) were extracted for each particle species and centrality bin. To disentangle thermal and collective effects, the mean kinetic freeze-out temperature ( ) was obtained from the intercept of the T versus mass relation, and the average transverse flow velocity ( ) was extracted from the slope of versus mean moving mass for pions, kaons, and protons. The results show that T increases and q decreases with centrality, indicating a hotter and more equilibrated system in central collisions. A clear mass dependence of T supports the presence of a multi-freeze-out scenario, with heavier particles decoupling earlier. Both and arise from peripheral to mid-central collisions before saturating toward central events, which may suggest the onset of collective behavior or changes in freeze-out dynamics. These observations provide new insights into the thermal and dynamical properties of the medium created in heavy-ion collisions at the LHC.

The transverse momentum distributions of charged hadrons produced in proton-proton collisions at center-of-mass energies ( ) of 0.9 TeV and 2.36 TeV, as measured by the CMS detector at the Large Hadron Collider (LHC), have been analyzed within various pseudorapidity classes utilizing the thermodynamically consistent Tsallis distribution. The fitting procedure resulted in the key parameters, namely, effective temperature (T), non-extensivity parameter (q), and kinetic freezeout volume (V). Additionally, the mean transverse momentum ( ) and initial temperature (T_i ) of the particle source are determined through the fit function and string percolation method, respectively. An alternative method is employed to calculate the kinetic freezeout temperature ( ) and transverse flow velocity ( ) from T. Furthermore, thermodynamic quantities at the freezeout, including energy density (ε), particle density (n), entropy density (s), pressure (P), and squared speed of sound ( ), are computed using the extracted T and q. It is also observed that, with a decrease in pseudorapidity, all thermodynamic quantities except V and q increase. This trend is attributed to greater energy transfer along the mid pseudorapidity. q increases towards higher values of pseudorapidity, indicating that particles close to the beam axis are far from equilibrium. Meanwhile, V remains nearly independent of pseudorapidity. The excitation function of these parameters (q) shows a direct (inverse) correlation with collision energy. The ε, n, s, and P show a strong dependence on collision energies at low pseudorapidities. Explicit verification of the thermodynamic inequality suggests the formation of a highly dense droplet-like Quark-Gluon Plasma (QGP). Additionally, the inequality is explicitly confirmed, aligning with the evolution of the produced fireball.

In this study, we systematically investigate the dynamics of various hadrons namely π ⁺, π ⁻, K ⁺, K ⁻, p, p ¯ , Λ, Λ ¯ , Ξ⁻ and Ξ ¯ + produced in central Au–Au collisions. We analyze data of AGS and RHIC, which span a broad range of collision energies, ranging from s NN = 1.9 to 200 GeV. To analyze the transverse momentum (p _T ) and transverse mass (m _T ) distributions, we employ a two-component standard distribution function, achieving a very good representation of the experimental data across these energy regimes. We extract key thermodynamic parameters, including the effective temperature T, the mean transverse momentum 〈p _T 〉, and the initial temperature T _i , and analyze their dependence on the values of collision energy and particle mass. Our findings reveal a distinct transition behaviour around s NN = 19.6 GeV . Below s NN = 19.6 GeV , the values of T, 〈p _T 〉, and T _i increase monotonically for all hadrons due to higher energy transfer into the system. Above this energy threshold, these extracted parameters plateau, suggesting that the additional energy is utilized as latent heat for phase transition rather than increasing the system’s temperature. These observations delineate two distinct regions: a hadron-dominated region at lower energies and a parton-dominated region at higher energies, each potentially indicative of different phases of matter, with the latter possibly signalling the onset of a quark–gluon plasma. The study thus provides critical insights into the complex interplay of thermodynamics, phase transitions, and particle interactions in high-energy Au–Au collisions.