NNLO fermionic corrections to the charm quark mass dependent matrix elements in (B)over-bar→ Xsγ

We compute the virtual O(alpha(2)(s)) fermionic contributions to the charm quark mass dependent matrix elements of the (B) over bar -> X-s gamma decay. In the case of a massless quark loop insertion into the gluon propagator, our result obtained as an expansion in z = m(c)(2)/m(b)(2) and an exact expression in terms of multi-fold MB integrals, confirms the findings of Bieri, Greub and Steinhauser [22]. In the case of a b-quark loop insertion, we observe large differences between the actual massive case and the massless approximation. These turn out, as expected, to be less pronounced for the charm quark.