Heavy flavour quarks in ep collisions are produced mostly from pair-production through a fusion of a virtual photon and a gluon from the proton. Therefore, the production cross sections provide information on the gluon distribution in the proton. The presence of a hard scale from the heavy quark mass, in principle, ensures that the cross sections are calculable through pQCD. Measurements in ep collisions, however, show that the calculations reasonably agree with the data in general, but underestimate the cross sections in some regions of phase space.
Charm cross sections; Beauty cross sections; ep scattering; c fragmentation; Proton structure functions
