411 research outputs found
Soft parton resummation in the current region of semi-inclusive deep inelastic scattering
We discuss resummation of large logarithmic terms that appear in the
cross-section of semi-inclusive DIS in the case when the final-state hadron
follows the direction of the incoming electroweak vector boson in the c.m.
frame of the vector boson and the initial-state proton.Comment: Presented at the 8th International Workshop on Deep Inelastic
Scattering (DIS2000), Liverpool, U.K., April 2000; 4 pages, 2 fig
Near Future Perpectives of QCD Spin Studies
We consider the physics motivations and perspectives for the study of spin
phenomena at the future high energies accelerators. The possibilities to use
the already operating machines are also discussed. It is emphasized that the
present status of QCD spin studies necessarily requires a wide range of spin
measurementsComment: 44 pages with 8 figures available by request from authors, IHEP
93-39, LaTe
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
Heavy-quark parton distribution functions and their uncertainties
We investigate the uncertainties of the heavy-quark parton distribution functions in the variable flavor number scheme. Because the charm- and bottom-quark parton distribution functions (PDFs) are constructed predominantly from the gluon PDF, it is a common practice to assume that the heavy-quark and gluon uncertainties are the same. We show that this approximation is a reasonable first guess, but it is better for bottom quarks than charm quarks. We calculate the PDF uncertainty for t-channel single-top-quark production using the Hessian matrix method, and predict a cross section of 2.12+0.32-0.29 pb at run II of the Tevatron
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