Analysis of strongly intensive quantities for event-by-event transverse momentum and multiplicity fluctuations using the AMPT model

Abstract

Strongly intensive quantities Σ[P T , N] and Δ[P T , N] have become one of the important tools in study of phase transitions and critical points in high energy heavy-ion collisions. In this paper the properties of Σ[P T , N] and Δ[P T , N] are discussed within different colliding nuclei systems generated by the AMPT model. The combined event method are proposed to simulate the model of independent sources in which Σ[P T , N] and Δ[P T , N] are independent of the number of original events. The effects of transverse momentum, pseudorapidity and parton cascade are also discussed.

Energy and system size dependence of strongly intensive fluctuation measures in heavy-ion collisions at FAIR energies

“…Events corresponding to IPM may be simulated by event mixing technique [44,50,56]. There are a variety of mixed event models [50]. The one adopted in the present study, gives results identical to the IPM in the limit of infinite number of original and mixed events.…”

“…However, a remarkable system size dependence is observed with the largest values of Δ[p T , N] and Σ[p T , N], measured in peripheral Pb-Pb collisions. Wu et al [50] have studied ebe fluctuations using these variables in the framework of AMPT and MIS models in the energy range, s NN = 7-200 GeV. However, a detailed study of the dependence of these variables on collision centrality and centrality bin width is needed so as to test that to what extent the volume fluctuations may be kept under control by selection of centrality bins of proper widths.…”

“…The strongly intensive quantities have a characteristic property [44,50], that their values are equal to one for independent emission of particles. This is the assumption of independent particle model (IPM) [55].…”

“…This is the assumption of independent particle model (IPM) [55]. Events corresponding to IPM may be simulated by event mixing technique [44,50,56]. There are a variety of mixed event models [50].…”

“…This might be attributed to the fact that for a given Δη same p T cuts are applied to all energies but the η and p T distributions are quite different at different energies. It has been reported [50] that Δ[p T , N] and Σ[p T , N] values have different η and p T dependence at different energies. The findings based on mixed events analyses, however, do not show any energy dependence.…”