Effect of in-medium nucleon-nucleon cross section on proton-proton momentum correlation in intermediate energy heavy-ion collision

TL;DR

This study investigates how in-medium nucleon-nucleon cross sections affect proton-proton momentum correlations in intermediate energy heavy-ion collisions, revealing different emission mechanisms at various rapidities and impact parameters.

Contribution

It introduces a detailed analysis of in-medium nucleon-nucleon cross section effects on proton-proton correlations using quantum molecular dynamics and analytical methods.

Findings

In-medium cross section significantly affects correlations at small impact parameters.

No effect of in-medium cross section on mid-rapidity proton correlations.

Emission mechanisms differ between rapidity regions.

Abstract

The proton-proton momentum correlation function from different rapidity regions are systematically investigated for the Au + Au collisions at different impact parameters and different energies from 400$A$ MeV to 1500$A$ MeV in the framework of the isospin-dependent quantum molecular dynamics model complemented by the $Lednick\acute{y}$ and $Lyuboshitz$ analytical method. In particular, in-medium nucleon-nucleon cross section dependence of the correlation function is brought into focus, while the impact parameter and energy dependence of the momentum correlation function are also explored. The sizes of the emission source are extracted by fitting the momentum correlation functions using the Gaussian source method. We find that the in-medium nucleon-nucleon cross section obviously influence the proton-proton momentum correlation function which is from the whole rapidity or projectile/target rapidity region at smaller impact parameters, but there is no effect on the mid-rapidity proton-proton momentum correlation function, which indicates that the emission mechanism differs between projectile/target rapidity and mid-rapidity protons.