Abstract

We discuss the fact that k(t)-factorization calculations for heavy-quark production include only the gg -> Q (Q) over bar contribution. The cases of fixed-flavor-number scheme and variable-flavor-number scheme calculations are analyzed separately. For the latter, we show that, similarly to the collinear factorization, the main contribution is given by the Qg -> Qg process. In this scheme, calculations including only the gg contribution should show a large discrepancy with the data. We show that, if they do not, it is because they include (effectively) a large K factor.