Variable flavor number schemes versus fixed order perturbation theory   for charm quark electroproduction
  Data for D*(2010) meson electroproduction in the range 10 < Q2 < 1350 GeV^2 has recently been presented by the ZEUS collaboration at HERA. We use these results together with previously published data for Q2 > 1 GeV^2 to test whether one can distinguish between different theoretical schemes for charm quark electroproduction. We find that up to the largest Q2 measured, it is not possible to make such a differentiation. Then we point out the regions where differences between the various schemes arise. 
A. Chuvakin, J. Smith, B. W. Harris