Medium Modifcations of Mesons in Elementary Reactions and Heavy-Ion Collisions

TL;DR

This paper reviews experimental evidence for modifications of vector mesons in nuclear media, showing mass drops and width increases for certain mesons, with comparisons to theoretical models.

Contribution

It provides a comprehensive review of experimental data on meson modifications in nuclear matter and compares these findings with recent theoretical models.

Findings

$ ho$, $ ext{omega}$, and $ ext{Phi}$ mesons show mass drops in medium.

Widths of $ ext{omega}$ and $ ext{Phi}$ mesons increase significantly in medium.

Conflicting results exist for $ ho$ meson mass shifts and broadening.

Abstract

Experimental searches for modifications of vector mesons in the nuclear medium are reviewed. Data on $\rho,\omega$ and $\Phi$ mesons are presented. The results have been obtained in elementary reactions with proton and photon beams as well as in heavy-ion collisions. Compared to the free particle properties, the $\omega$ and $\Phi$ meson are found to drop in mass at normal nuclear matter density by 9-14% and 3.5% whereas their widths are reported to increase by factors of about 16 and 3.6, respectively. For the $\rho$ meson, conflicting results on in-medium mass shifts and broadening have been published. The experimental data are compared to recent model calculations.