Hanbury Brown-Twiss correlation of $\phi\phi$ with in-medium mass modification

Abstract

We study the impacts of the squeezing effect caused by in-medium mass modification on the Hanbury Brown-Twiss (HBT) correlation of $\phi\phi$ using a hydrodynamical source. The squeezing effect reduces the influence of transverse flow on the transverse distribution of $\phi$ emitting source while expanding the longitudinal source distribution. This trend becomes more noticeable as the transverse momentum increases, resulting in an enlargement of the HBT radii for $\phi\phi$ . Notably, this enlargement is particularly evident with higher transverse pair momentum. As a result, the HBT radii of $\phi\phi$ increase as transverse pair momentum increases instead of showing a consistent crease, showcasing non-flow behavior of HBT radii in hydrodynamical sources. Both Gaussian fitting and Levy fitting support the conclusion.