Work

Unlocking the initial neutron density distribution from the two-pion HBT correlation function in heavy-ion collisions

Year: 2025

Type: article

Abstract: Revealing the neutron density distribution in the nucleus is one of the crucial tasks of nuclear physics. Within the framework of the ultrarelativistic quantum molecular dynamic model followed by a correlation afterburner program, we investigate the effects of the initial neutron density distribution on the charged-pion yield ratio π − / π + , the two-pion momentum correlation function, and the emission source dimension. It is found that the π − / π + ratio is sensitive to the initial neutron density distribution and the impact parameter, especially for collisions at large impact parameter. However, the charge splitting in the correlation functions between positively π + π + and negatively π − π − , as well as the source radii and volumes extracted exhibit a stronger dependence on the initial neutron density distribution, but a weaker dependence on the impact parameter. The present study highlights that π + π + and π − π − correlation functions in heavy-ion collisions could be used to probe the initial neutron density distribution of nuclei.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2025.139963