A novel approach for studying two-particle momentum correlation function in relativistic nuclear collisions

Abstract

Two particle momentum correlation functions provide a nontrivial tool for probing the strong interaction and/or extracting particle emission source information in relativistic nuclear collisions. Although transport models can describe the microscopic phase-space evolution of the collision system, calculating correlation functions within the framework of transport models remains challenging. In this paper, we employ the mixed-event technique to calculate two particle momentum correlation function as $C(k^{\ast })=\mathcal{N}\hat{I}¾(k^{\ast })\frac{N_{\mathrm{same}}(k^{\ast })}{N_{\mathrm{mixed}}(k^{\ast })}$ based on the parton and hadron cascade model PACIAE simulated final hadronic state (FHS) with introducing a modification factor $\hat{I}¾(k^{\ast })$ to improve the treatment of final-state interactions and quantum statistics effects in the PACIAE model. The simulated results show good agreement with the ALICE data for $Kp$, $pp$, $p\hat{I}›$, and $\hat{I}›\hat{I}›$ momentum correlation functions in $pp$ collisions at $\sqrt{s}=7$ TeV. On the other hand, the particle emission source radius of the correlated pairs are also evaluated based on the simulated FHS self-consistently. Since the PACIAE model employs hadron-hadron cross sections derived from the additive quark model, the calculation of two-particle momentum correlation functions does not require prior assumptions about the interaction between the two correlated particles. This successful ``PACIAE + modification factor" approach may shed light on the future study of momentum correlation functions for dimesons, dibaryons, and even diexotic hadrons.

4 pages,1 figure