Coherent description of D*^± production in e ⁺ e ^- and low-Q ² ep collisions

Abstract

We present new sets of fragmentation functions for D*^± mesons, both at leading and next-to-leading order. They are determined by fitting LEP1 data on inclusive D*^± production in e ⁺ e ^- annihilation. In one of the sets, we take the charm-quark fragmentation function to be of the form proposed by Peterson et al. and thus obtain updated values of the ε _c parameter and the c → D*^± branching ratio. The new fragmentation functions lead to an excellent description of other e ⁺ e ^- data with centre-of-mass energies between 10 and 35 GeV. They also nicely agree with recent HERA data on inclusive D*^± photoproduction in ep collisions, which may be considered as a test of the universality of the fragmentation into D*^± mesons.