Charm Fluctuations and Deconfinement
Pre-published on:
May 02, 2024
Published on:
November 06, 2024
Abstract
We establish that the charmed hadrons start dissociating at the chiral crossover temperature, ${T_{pc}}$, leading to the appearance of charm degrees freedom carrying fractional baryon number. Our method is based on analyzing the second and fourth-order cumulants of charm (${C}$) fluctuations, and their correlations with baryon number (${B}$), electric charge (${Q}$) and strangeness (${S}$) fluctuations. The first-time calculation of the ${QC}$ correlations on the high statistics datasets of the HotQCD Collaboration enables us to disentangle the contributions from different electrically-charged charm subsectors in the hadronic phase. In particular, we see an enhancement over the PDG expectation in the fractional contribution of the ${|Q|}=2$ charm subsector to the total charm partial pressure for ${T<T_{pc}}$; this enhancement is in agreement with the Quark Model extended Hadron Resonance Gas (QM-HRG) model calculations. Furthermore, the agreement of QM-HRG calculations with the projections onto charmed baryonic and mesonic correlations in different charm subsectors indicates the existence of not-yet-discovered charmed hadrons in all charm subsectors below ${T_{pc}}$. We aim at determining the relevant degrees of freedom in temperature range ${T_{pc}<T<340 \text{ MeV}}$ by assuming the existence of a non-interacting gas of charmed quasi-particles composed of meson, baryon and quark-like excitations above $T_{pc}$. Our data suggest that the particles with quantum numbers consistent with quarks start appearing at $T_{pc}$.
DOI: https://doi.org/10.22323/1.453.0200
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating
very compact bibliographies which can be beneficial to authors and
readers, and in "proceeding" format
which is more detailed and complete.