Deuteron yields near the QCD phase transition

TL;DR

This study explores how the QCD phase transition and critical fluctuations near the critical end point affect deuteron yields in heavy-ion collisions, revealing mild enhancements due to critical phenomena.

Contribution

It introduces a combined approach using the functional renormalization group, nucleon coalescence, and effective field theory to analyze deuteron production near the QCD critical point.

Findings

Baryon density correlations are enhanced near the CEP.

Deuteron yield enhancement from critical fluctuations is mild.

Low-energy collisions show deviations from the critical region.

Abstract

We investigate the influence of QCD phase transition and critical fluctuations of the critical end point (CEP) on the deuteron yield within the functional renormalization group (fRG) approach, by using the nucleon coalescence model and a low energy effective field theory of quarks and mesons. It is found that the two-point baryon density correlation function is enhanced in a narrow region radiated from the CEP along the phase boundary. The deuteron yield arising from the two-point baryon correlation is small compared to the leading-order contribution, which is attributed to the fact that in the regime of low collision energy, i.e., the region of large baryon chemical potential, the freeze-out curves deviate from the critical region, resulting in that the enhancement of the deuteron yield stemming from the critical fluctuations near the CEP is mild.