How sensitive are high-pT electron spectra at RHIC to heavy quark energy loss?

In nucleus-nucleus collisions, high-p(T) electron spectra depend on the medium modified fragmentation of their massive quark parents, thus giving novel access to the predicted mass hierarchy of parton energy loss. Here we calculate these spectra in a model, which supplements the perturbative QCD factorization formalism with parton energy loss. In general, we find-within large errors-rough agreement between theory and data on the single inclusive electron spectrum in pp, its nuclear modification factor R-AA(e), and its azimuthal anisotropy upsilon(e)(2). However, the nuclear modification factor depends on the relative contribution of charm and bottom production, which we find to be affected by large perturbative uncertainties. In order for electron measurements to provide a significantly more stringent test of the expected mass hierarchy, one must then disentangle the b- and c-decay contributions, for instance by reconstructing the displaced decay vertices. (c) 2006 Elsevier B.V. All rights reserved.