Thermodynamics of charmed hadrons across chiral crossover from lattice QCD

TL;DR

This study uses lattice QCD to analyze how charmed hadrons behave across the chiral crossover, revealing the emergence of unobserved states, the breakdown of the Hadron Resonance Gas model, and signs of charm deconfinement.

Contribution

It provides new insights into the thermodynamics of charmed hadrons, highlighting the role of unobserved states and the limitations of existing models near the crossover.

Findings

Enhanced contributions from unobserved charmed hadrons below the crossover.

Breakdown of the Hadron Resonance Gas model at the chiral crossover.

Evidence for survival of low-lying charmed hadron excitations above the crossover.

Abstract

We use up to fourth-order charm fluctuations and their correlations with net baryon number, electric charge, and strangeness fluctuations, calculated within the framework of lattice QCD, to study the continuum partial pressure contributions of charmed baryons and mesons. We show that, at and below the chiral crossover temperature, these partial pressures receive enhanced contributions from experimentally unobserved charmed hadrons predicted by the Quark Model. Additionally, we demonstrate that at the chiral crossover, the Hadron Resonance Gas description breaks down, signaling the modification of open charm hadrons and thereby implying the onset of charm deconfinement. We present evidence for the survival of low-lying non-radial $1S$ and $1P$ hadron-like excitations above the chiral crossover, which hints at the sequential melting of charmed hadrons. Finally, we investigate the continuum partial pressure contribution of charm quark-like excitation that emerges at the chiral crossover and calculate its temperature-dependent in-medium mass.