Measurements of open charm hadrons at the STAR experiment

Abstract

Because of their large masses, charm quarks are predominantly produced in the early stages of the heavy-ion collisions via hard scatterings. Therefore, they experience the entire evolution of the Quark-Gluon Plasma created in such collisions. Compared to light quarks, charm quarks thermalize more slowly. Therefore, the open charm hadrons present a unique probe to the properties of the hot and dense nuclear matter by measuring their energy loss and degree of thermalization in the medium. Furthermore, with the combined measurements of D0 and Ds mesons, we can study multiple modes of coalescence of charm quarks with light quarks in heavy-ion collisions. Heavy Flavor Tracker at the STAR experiment enables full topological reconstruction of open charm hadrons which greatly improves measurements of D0 mesons and opens the door to reconstructing the Ds mesons for the first time at RHIC. In this paper, we present the nuclear modification factor and azimuthal anisotropy for the D0 and Ds mesons as well as the ratio of Ds/D0 in Au+Au collisions at the center-of-mass energy .