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

Frontiers of QCD with Precision nPDFs

Searches for new physics will increasingly depend on identifying deviations from precision Standard Model (SM) predictions. Quantum Chromodynamics (QCD) will necessarily play a central role in this endeavor as it provides the framework for the parton model. However, as we move to higher orders and into extreme kinematic regions, we begin to see the full complexities of the QCD theory. Recent theoretical developments improve our ability to analyze both proton and nuclear PDFs across the full kinematic range. These developments are incorporated into the new nCTEQ15 PDFs, and we review these developments with respect to future measurements, and identify areas where additional effort is required.Comment: Published in the "6th International conference on Physics Opportunities at Electron-Ion colliders (POETIC6)

q_T Uncertainties for W and Z Production

Analysis of semi-inclusive DIS hadroproduction suggests broadening of transverse momentum distributions at small x below 1E-3 ~ 1E-2 which can be modeled in the Collins-Soper-Sterman formalism by a modification of impact parameter dependent parton densities. We investigate these consequences for the production of electroweak bosons at the Tevatron and the LHC. If substantial small-x broadening is observed in forward Z boson production in the Tevatron Run-2, it will strongly affect the predicted q_T distributions for W and Z boson production at the LHC.Comment: 4 pages, 2 figures; contribution to the XIII International Workshop on Deep Inelastic Scattering (DIS 2005