Heating triangle singularities in heavy ion collisions

TL;DR

This paper predicts that triangle singularities in hadron spectroscopy are significantly affected by the hot medium in heavy ion collisions, acting as a filter that alters observed resonance peaks under specific conditions.

Contribution

It introduces a novel analysis of how finite temperature in heavy ion collisions influences triangle singularities, providing criteria for when medium effects modify spectral features.

Findings

Medium effects can reduce triangle singularity peaks by up to two orders of magnitude at T ~ 150 MeV.

Conditions for significant medium effects include comparable intermediate hadron flight-time and fireball lifetime.

Peaks in heavy ion collisions are more likely due to hadrons than rescattering effects under certain conditions.

Abstract

We predict that triangle singularities of hadron spectroscopy can be strongly affected in heavy ion collisions. To do it we examine various effects on the singularity-inducing triangle loop of finite temperature in the terminal hadron phase. It appears that peaks seen in central heavy ion collisions are more likely to be hadrons than rescattering effects under two conditions. First, the flight-time of the intermediate hadron state must be comparable to the lifetime of the equilibrated fireball (else, the reaction mostly happens in vacuo after freeze out). Second, the medium effect over the triangle-loop particle mass or width must be sizeable. When these (easily checked) conditions are met, the medium quickly reduces the singularity: at T about 150 MeV, even by two orders of magnitude, acting then as a spectroscopic filter.