Direct photon production in polarized hadron collisions at collider and fixed target energies

Recently determined next-to-leading order sets of polarized parton distributions are used to study large-P-T (P) over right arrow (P) over right arrow–>gamma + X at root s = 38, 100, and 500 GeV. Certain conversion terms, necessary to use the above sets, are determined. It is concluded that, to distinguish between the above sets, planned experiments at BNL RHIC should be successful, in particular, at a c.m. photon pseudorapidity similar or equal to 1, and that a proposed HERA-(N) over right arrow fixed target experiment should have a rather large accuracy at relatively large x(T) (=2p(T)/root s)

Polarized photoproduction of heavy quarks in next-to-leading order

The results of a next-to-leading order calculation of heavy quark production in longitudinally polarized photon-nucleon collisions are presented. At c.m. energy root S = 10 GeV, for gamma + p –> c + X, cross sections differential in the transverse momentum and rapidity of the charmed quark c and the corresponding asymmetries are presented; also, as functions of root S, integrated cross sections, K-factors and the corresponding asymmetries an given. Errors in the asymmetries are estimated and the possibility to distinguish between three scenarios differing essentially in the polarized gluon distribution is discussed. (C) 2000 Elsevier Science B.V. All rights reserved

ONE-LOOP CORRECTIONS TO LEPTON-PAIR PRODUCTION BY TRANSVERSELY POLARIZED HADRONS

A complete calculation of QCD higher order corrections (HOC) at one loop for Drell-Yan lepton pair production by transversely polarized hadrons is presented. Production via both gamma and Z is taken into account. For p(up arrow)p(up arrow) –> l(-)l(+) + X,K-factors well exceeding unity are found and, in particular near the Z peak, significant rates may be anticipated. The dominance of HOC by soft, collinear and virtual gluons is also studied

Inclusive leptoproduction of a transversely polarized baryon on a transversely polarized proton

The processes lp up arrow lY up arrow + X, where Y = Lambda or Sigma(+), are studied, including one-loop higher order corrections (HOC). In constructing the transversity distributions, Soffer’s inequality is taken into account. HOC are found to be small in comparison with those in Drell-Yan l(-)l(+) production by transversely polarized baryons and in transversely polarized baryon-antibaryon production in e(-)e(+) collisions. The reason for this difference is discussed

Next-to-leading order corrections to heavy flavor production in longitudinally polarized photon-nucleon collisions

A complete next-to-leading order calculation of longitudinally polarized heavy quark photoproduction is presented. All results of the perturbative calculation are given in detail. For reactions and energies of interest cross sections differential in the transverse momentum and rapidity of the heavy quark, total cross sections, and the corresponding asymmetries are given. Errors in the asymmetries are estimated and the possibility to distinguish between various scenarios of the polarized gluon distribution is discussed. Our results are compared with other related publications

Polarized photoproduction of large-p(T) hadron pairs as a probe of the polarized gluon distribution

Production of large-p(T) hadron pairs by a polarized photon on a longitudinally polarized proton towards probing the polarized gluon distribution is studied. Resolved photon contributions and the effect of changing the scales are taken into account, and predictions are presented. A very recent experimental result at c.m. energy 7.18 GeV is compared to our predictions extended down to this energy. A proper combination of cross sections is also considered