Collinear subtractions in hadroproduction of heavy quarks

We present a detailed discussion of the collinear subtraction terms needed to establish a massive variable-flavor-number scheme for the one-particle inclusive production of heavy quarks in hadronic collisions. The subtraction terms are computed by convoluting appropriate partonic cross sections with perturbative parton distribution and fragmentation functions relying on the method of mass factorization. We find (with one minor exception) complete agreement with the subtraction terms obtained in a previous publication by comparing the zero-mass limit of a fixed-order calculation with the genuine massless results in the (MS) over bar scheme. This presentation will be useful for extending the massive variable-flavor-number scheme to other processes.