A Heavy Ion Fireball freeze-out Dipion Cocktail for Au-Au Collisions at $\sqrt{s_{NN}}$=200 GeV $p_t$ dependence(Part 2)

TL;DR

This paper models the $p_t$ dependence of dipion production in Au-Au collisions at 200 GeV, combining minijet fragmentation and thermal resonance production to understand re-scattering effects and resonance modifications.

Contribution

It extends the dipion cocktail model by incorporating $p_t$ dependence and re-scattering effects, linking the $ ho$ resonance mass shift to the re-scattering region size.

Findings

Re-scattering region size estimated from interference effects.

$ ho$ resonance mass shift related to re-scattering parameter $oldsymbol{\alpha}$.

Model fits RHIC STAR data successfully.

Abstract

In this paper we use methods developed in Part 1 of The Dipion Cocktail, to fit the $p_t$ dependence of dipions for mid-central Au-Au collisions at $\sqrt{s_{NN}}$=200 GeV. For the minijet fragmentation part we use PYTHIA fragmentation as described in Part 1. For the thermal resonance production we use an exponential growth behavior. The interference between the direct production of dipion pairs from non-resonance minijet fragmentation and re-scattering through resonance states gives a measure of the size of the re-scattering region. This size is contain in the $\alpha$ parameter of Part1. We assumed a relationship between the $\alpha$ parameter and the mass shift of the $\rho$ resonance. The data used for the fits comes from the RHIC collider as measured in the STAR experiment.