60 research outputs found
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
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