Multiplicity dependence of the freezeout parameters in high energy hadron-hadron collisions

Abstract

We examined the transverse momentum spectra of various identified particles, across different multiplicity classes in proton-proton collisions at a center-of-mass energy of $\sqrt{s}$ = 7 TeV. Utilizing the Tsallis and Hagedorn models, parameters relevant to the bulk properties of nuclear matter were extracted. Both models exhibit good agreement with experimental data. In our analyses, we observed a consistent decrease in the effective temperature for the Tsallis model and the kinetic or thermal freeze-out temperature for the Hagedorn model, as we transition from higher multiplicity (class-I) to lower multiplicity (class-X). Additionally, the transverse flow velocity experiences a decline from class-I to class-X. The normalization constant which represents the multiplicity of produced particles is observed to decrease as we move towards higher multiplicity classes. While the effective and kinetic freeze-out temperatures, as well as the transverse flow velocity, show a mild dependency on multiplicity for lighter particles, this relationship becomes more pronounced for heavier particles. Various particle species are observed to undergo decoupling from the fireball at distinct temperatures: lighter particles exhibit lower temperatures, while heavier ones show higher temperatures, thereby supporting the concept of multiple freeze-out scenarios. Moreover, we identified a positive correlation between the kinetic freeze-out temperature and transverse flow velocity, a scenario where particles experience stronger collective motion at higher freeze-out temperature. The reason for this positive correlation is that as the multiplicity increases, more energy is transferred into the system. This heightened energy causes greater excitation and pressure within the system, leading to a quick expansion.

arXiv comment13 pages, 3 figures, to be published in Chinese Physics C

References in corpus (30)

• Thermal phenomenology of hadrons from 200 AGeV S+S collisions
• Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR
• Heavy Ion Collisions: The Big Picture, and the Big Questions
• Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review
• The Tsallis Distribution in Proton-Proton Collisions at $\sqrt{s}$ = 0.9 TeV at the LHC
• Spectra and radial flow at RHIC with Tsallis statistics in a Blast-Wave description
• Measurement of neutral mesons in p+p collisions at sqrt(s) = 200 GeV and scaling properties of hadron production
• Systematic properties of the Tsallis Distribution: Energy Dependence of Parameters in High-Energy p-p Collisions
• Non-Extensive Approach to Quark Matter
• Signatures of Thermal Dilepton Radiation at RHIC
• Hadron spectra in p+p collisions at RHIC and LHC energies
• System size dependence of hadron $p_T$ spectra in p+p and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
• Systematic Analysis of the Non-extensive Statistical Approach in High Energy Particle Collisions - Experiment vs. Theory
• Effect of pre-equilibrium phase on $R_{AA}$ and $v_2$ of heavy quarks in heavy ion collisions
• Systematics of Kinetic Freeze-out Properties in High Energy Collisions from STAR
• Propagation of heavy baryons in heavy-ion collisions
• Little-Bang and Femto-Nova in Nucleus-Nucleus Collisions
• The Exact Evolution Equation of the Curvature Perturbation for Closed Universe
• Photon production from non-equilibrium QGP in heavy ion collisions
• Radial Flow and Differential Freeze-out in Proton-Proton Collisions at $\sqrt{s}=7$ TeV at the LHC
• Strange Hadron Resonances and QGP Freeze-out
• On the Use of the Tsallis Distribution at LHC Energies
• Identified particle spectra in Pb-Pb, Xe-Xe and p-Pb collisions with Tsallis blast-wave model
• Hadron Spectra Parameters within the Non-Extensive Approach
• Pseudorapidity dependence of the $p_T$ spectra of charged hadrons in $pp$ collisions at $\sqrt{s}$ = 0.9 and 2.36 TeV
• Mass hierarchy and energy scaling of the Tsallis--Pareto parameters in hadron productions at RHIC and LHC energies
• Systematics of chemical freeze-out parameters in heavy-ion collision experiments
• Systematic analysis of the pp collisions at LHC energies with Tsallis function
• Dependence of temperatures and kinetic freeze-out volume on centrality in Au-Au and Pb-Pb collisions at high energy
• Particle species and energy dependencies of freeze-out parameters in high-energy proton-proton collisions

Cited by in corpus (2)

• Comparative Analysis of Jet and Underlying Event Properties Across Various Models as a Function of Charged Particle Multiplicity at 7 TeV
• Comment on "Evaluation of kinetic freeze-out properties in different relativistic heavy-ion collision systems at \sqrtsNN = 200 GeV'' (Eur. Phys. J. Plus (2025) 140:179) https://doi.org/10.1140/epjp/s13360-025-06119-0