Heavy Quark Parton Distribution Functions

We present the CTEQ6HQ parton distribution set which is determined in the general variable flavor number scheme which incorporates heavy flavor mass effects; hence, this set provides advantages for precision observables which are sensitive to charm and bottom quark masses. We describe the analysis procedure, examine the predominant features of the new distributions, and compare with previous distributions. We also examine the uncertainties of the strange quark distribution and how the the recent NuTeV dimuon data constrains this quantity.Comment: 5 pages, 2 figures; contribution to the XIII International Workshop on Deep Inelastic Scattering (DIS 2005

Heavy Quarks: Lessons Learned from HERA and Tevatron

We review some of the recent developments which have enabled the heavy quark mass to be incorporated into both the calculation of the hard-scattering cross section and the PDFs. We compare and contrast some of the schemes that have been used in recent global PDF analyses, and look at issues that arise when these calculations are extended to NNLO.Comment: 11 pages, 9 figures, to appear in the proceedings of the Ringberg Workshop "New Trends in HERA Physics 2008