A Description of the Transverse Momentum Distributions of Charged Particles Produced in Heavy Ion Collisions at RHIC and LHC Energies

Abstract

By assuming the existing of memory effects and long-range interactions in the hot and dense matter produced in high energy heavy ion collisions, the nonextensive statistics together with the relativistic hydrodynamics including phase transition is used to discuss the transverse momentum distributions of charged particles produced in heavy ion collisions. It is shown that the combined contributions from nonextensive statistics and hydrodynamics can give a good description to the experimental data in Au+Au collisions at √ = 200 GeV and in Pb+Pb collisions at √ = 2.76 TeV for ± , ± in the whole measured transverse momentum region, and for ( ̅ ) in the region of ≤ 2.0 GeV/c. This is different from our previous work, where, by using the conventional statistics plus hydrodynamics, the describable region is only limited in ≤ 1.1 GeV/c. Keywords：Nonextensive statistics; relativistic hydrodynamics; phase transition; transverse momentum distribution PACS Number(s): 25.75.Ag, 25.75.Ld, 25.75.Dw, 13.85.-t distributions [9-12], have been extensively studied in nuclear collisions at both RHIC and LHC energies. These investigations have shown a fact that the matter created in these collisions is in the state of strongly coupled quark-gluon plasma (sQGP) exhibiting a clear collective behavior nearly like a perfect fluid with very low viscosity [13-31]. Therefore, the movement of sQGP can be described in the scope of relativistic hydrodynamics which connects the static aspects of sQGP and the dynamical aspects of heavy ion collisions [32]. In our previous work [33], by considering the effects of thermalization, we once used a hydrodynamic model incorporating phase transition in analyzing the transverse momentum distributions of identified charged particles produced in heavy ion collisions. In that model, the quanta of hot and dense matter are supposed to observe the standard statistical distributions and the experimental measurements in Au+Au collisions at √ = 200 and 130 GeV can be well matched up in the region of ≤ 1.1 GeV/c. Known from the investigations in Ref. [34, 35], the memory effects and long-range force might appear in the hot and dense matter. This guarantees, at least to a certain extent, the reasonableness of nonextensive statistical approach in describing the thermal motions of quanta of hot and dense matter. Hence, in this paper, on the basis of hydrodynamics taking phase transition into considerations, we will use nonextensive statistics instead of conventional statistics to simulate the transverse collective flow of the matter created in collisions. The nonextensive statistics is also known as Tsallis nonextensive thermostatistics, which was first proposed by C. Tsallis in 1988 in his pioneering work [36]. This statistical theory overcomes the shortcomings of the conventional statistics in many physical problems with long-range interactions, long-range microscopic memory, or fractal space-time constrains. It has a wide range of applications in astrophysical self-gravitating systems [37], cosmology [38], the sola...

A New Description of Transverse Momentum Spectra of Identified Particles Produced in Proton-Proton Collisions at High Energies

“…Although the topic has been extensively studied in many papers for the SPS, RHIC and LHC heavy ion collisions and outlined the validity of a nonextensive statistical distribution [60][61][62][63][64][65][66], those investigations used the spectra in a wide p T range. It is unanimous that for the wide p T spectra, a two-, three-, or multi-component standard distribution is needed in the fit.…”

Energy density at kinetic freeze-out in Pb–Pb collisions at the LHC using the Tsallis distribution

“…The chemical potential μ will be taken to be zero in the present analysis presented below as is appropriate in the central rapidity region at LHC energies. There exist other, closely related, distributions that have been used to describe transverse momentum spectra, see [3][4][5][6][7][8] but these do not offer the advantage of connecting to a full thermodynamic description.…”

Rapidity and Energy Dependencies of Temperatures and Volume Extracted from Identified Charged Hadron Spectra in Proton–Proton Collisions at a Super Proton Synchrotron (SPS)

“…Although the topic has been extensively studied in many papers for the SPS, RHIC, and LHC heavy-ion collisions and outline the validity of a nonextensive statistical distribution [60][61][62][63][64][65][66], those investigations used the spectra in a wide p T range. It is unanimous that for the wide p T spectra, a two-, three-, or multi-component standard distribution is needed in the fit.…”