QCD corrections to double and single spin asymmetries in vector boson production at polarized hadron colliders

Abstract

The production of W ± and Z 0 bosons in collisions of longitudinally polarized protons allows to access various combinations of the polarized quark distributions from the study of double and single spin asymmetries. We compute the O(α s ) corrections to these asymmetries as function of the vector boson rapidity y in the hadron-hadron centre-of-mass frame. Detailed studies of the numerical impact of the next-to-leading order corrections are presented. The theoretical uncertainties of an extraction of polarized quark distributions from future vector boson production data are investigated in detail.

Effect of sea quarks on the single-spin asymmetries ALW± in polarized pp collisions at RHIC

“…There are also some theoretical studies on A W ± L based on available extractions or parametrizations of quark helicity distributions [33][34][35][36]. The predictions of A W ± L [15-21, 37, 38] are given, and it is found that the higher order QCD corrections are small [39][40][41][42]. Especially in Ref.…”

Threshold resummation of Drell–Yan rapidity distributions

“…The first term is the full NLO cross section reported in [8,19,20,21], which includes even the quark-gluon channel. The third and the fourth terms in eq.…”

QCD corrections to longitudinal spin asymmetries in W±-boson production at RHIC

“…Renormalization and factorization scales are taken to be equal, and are fixed to µ R = µ F = M W . The NLO scale dependence of the single and double spin asymmetries A L (y) and A LL (y) was studied in detail in [14]. It turns out to be very small, largely due to cancelations between the polarized and The W ± mass and width are taken [26] as M W = 80.399 GeV and Γ W = 2.085 GeV, and the Fermi coupling as G F = 1.16637 · 10 −5 GeV −2 .…”

“…Previous studies on NLO corrections to spin asymmetries in vector boson production [14] focused on the rapidity of the vector boson y, which is itself not directly measurable in W ± production, due to the unobserved neutrino in the final state. For the partonic interpretation of the asymmetries, the vector boson rapidity is very instructive, since at leading order (LO) it is directly related to the momentum fractions of the partons probed in both hadrons:…”

“…These corrections are known already for a long time for the fully inclusive asymmetries in gauge boson production [11,12] and for the asymmetries differential in the gauge boson rapidity [13,14]. Since W ± -boson production is observed only through the decay into a lepton and a neutrino, the W ± -boson rapidity cannot be measured directly.…”