Charm-energy loss and D-D correlations from a parton shower approach

Measurements of mesons containing charm or bottom quarks at high transverse momentum (PT) constitute an interesting set of probes for the nature of the interaction of hard partons with a QCD medium, as created in ultrarelativistic heavy-ion (A-A) collisions. Not only can D and B mesons to a reasonable accuracy be assumed to represent the hadronization of a b or c quark after passage through the medium (i.e., they explicitly reflect quark-medium interaction), but also their interaction physics is expected to be different from that of light partons traversing a medium: The quark mass restricts radiation phase space, leading to a reduction of both vacuum and medium-induced radiation, a phenomenon known as the "dead cone effect." Owing to this difference in physics, heavy quark interaction with the medium is usually treated in the leading parton energy-loss approximation, whereas the theory of light parton physics has moved to modeling the full medium-modified shower evolution. In this work, an attempt is made to create a more unified description of light parton and heavy quark physics at high PT by computing charm-medium interactions in terms of the nuclear suppression factor and back-to-back correlations using an in-medium shower evolution Monte Carlo code that is well tested for light parton physics and thus to verify whether the charm quark mass is sufficiently small compared to PT to allow an in-medium shower computation consistent with light partons, i.e., without changing or introducing new parameters.