Emergence of New Systematics for Open Charm Production in High Energy Collisions

TL;DR

This paper analyzes open charm hadron production in high-energy collisions using the Statistical Hadronization Model, revealing scaling behaviors and the impact of missing resonances, with implications for understanding charm quark hadronization.

Contribution

The study extends the SHMc to open charm production in various collision systems and links charm yield densities to charm-anticharm pairs, highlighting scaling laws and resonance effects.

Findings

Open charm yields scale with charm pair densities across systems.

The slope coefficient for charm baryons differs due to missing resonances.

Charm yield ratios are independent of collision energy and system size.

Abstract

We present the production systematics of open charm hadron yields in high-energy collisions and their description based on the Statistical Hadronization Model of charm (SHMc). The rapidity density of $D^0, D^+, D^{*+}, D_s^+$ mesons and $\Lambda_c^+$ baryons in heavy ion and proton-proton collisions is analyzed for different collision energies and centralities. The SHMc is extended to open charm production in minimum-bias and high-multiplicity pp collisions. In this context, we use the link established in [1,2], between the rapidity density of open charm hadron yields, $dN_i/dy$, and the rapidity density of charm-anticharm quark pairs, $dN_{c\bar c}/dy$. We demonstrate that, in pp, pA and AA collisions, $dN_i/dy$ scales in leading order with $dN_{c\bar c}/d\eta$ and for open charm mesons, $D^0,D^+$ and $D^{*+}$ the slope coefficient is quantified by the appropriate thermal density ratio calculated in the SHMc at the chiral crossover temperature, $T_c=156.5$ MeV. The slope coefficient for $dN_{\Lambda_c^+}/dy$ differs at $T_c$ by a factor of $1.97\pm 0.14$ which is attributed to missing charmed-baryon resonances in the PDG. It is also shown that $dN_i/dy$ exhibits power-law scaling with the charged-particle pseudo-rapidity density in high energy collisions and within uncertainties. Furthermore, presently available data on different ratios of open charm rapidity densities in high-energy collisions are independent of collision energy and system size, as expected in the SHMc.