Testing radiative energy loss at RHIC and at the LHC

The ratio of nuclear modification factors of high-pT heavy-flavored mesons to light-flavored hadrons (heavy-to-light ratio) is shown to be a sensitive tool to test medium-induced energy loss at RHIC and LHC energies. Heavy-to-light ratios of D mesons at the Relativistic Heavy Ion Collider RHIC in the region 7<pT<12 GeV, and of D and B mesons at the Large Hadron Collider LHC in the region 10<pT<20 GeV, are proposed for such a test. Finally, the perturbative uncertainties in the nuclear modification factor for electrons at RHIC are analyzed. Data from the PHENIX and STAR Collaborations are compatible with radiative energy loss provided the contribution of electrons from beauty decays is small compared to that from charm. The results stress the need to control the p-p baseline form charm and beauty production