Charm meson and charm-meson molecule in an expanding hadron gas

by Dr Liping He (University of Bonn，Germany)

Wednesday 27 Dec 2023, 16:00 → 17:00 Asia/Shanghai

We study the evolution of charm mesons after the kinetic freeze-out of the expanding hadron gas produced in a heavy-ion collision and the thermal correction to a loosely bound charm-meson molecule in a pion gas. The $\pi D^* \to \pi D^*$ reaction rates have t-channel singularities that give contributions inversely proportional to the thermal width of the $D$.  The ratio of the $D^0$ and $D^+$ production rate can differ significantly from those predicted using the measured $D^*$ branching fractions. The thermal correction of  loosely bound charm-meson molecule in a pion gas  comes primarily from the complex thermal energy shift of the charm-meson constituents. The remaining correction gives a tiny decrease in the binding energy of the molecule and a tiny change in its thermal width. These results are encouraging for the prospects of observing loosely bound charm-meson molecules in the hadron gas produced by the heavy-ion collisions.

何丽萍，本科，硕士毕业于兰州大学，博士毕业于俄亥俄州立大学，2021年以来在波恩大学做博士后，主要研究三角图奇点，X(3872)等奇特强子态的产生以及其在重离子碰撞产生的强子气体中的性质及演化。

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