Effects of $\rho$-meson width on pion distributions in heavy-ion collisions

TL;DR

This paper investigates how the finite width of the $ ho$ meson affects pion momentum distributions in heavy-ion collisions, showing that proper resonance treatment enhances low-$p_T$ pion spectra and improves agreement with experimental data.

Contribution

It introduces a method combining the S-matrix approach with a blast-wave model to accurately account for resonance widths in particle emission simulations.

Findings

Proper resonance treatment significantly modifies pion spectra.

Enhanced low-$p_T$ pion yields match experimental observations.

Improved modeling aligns with ALICE collaboration data.

Abstract

The influence of the finite width of $\rho$ meson on the pion momentum distribution is studied quantitatively in the framework of the S-matrix approach combined with a blast-wave model to describe particle emissions from an expanding fireball. We find that the proper treatment of resonances which accounts for their production dynamics encoded in data for partial wave scattering amplitudes can substantially modify spectra of daughter particles originating in their two body decays. In particular, it results in an enhancement of the low-$p_T$ pions from the decays of $\rho$ mesons which improves the quantitative description of the pion spectra in heavy ion collisions obtained by the ALICE collaboration at the LHC energy.