Single-Spin Asymmetries in W Boson Production at Next-to-Leading Order

Abstract

We present an analytic next-to-leading order QCD calculation of the partonic cross sections for single-inclusive lepton production in hadronic collisions, when the lepton originates from the decay of an intermediate electroweak boson and is produced at high transverse momentum. In particular, we consider the case of incoming longitudinally polarized protons for which parity-violating single-spin asymmetries arise that are exploited in the $W$ boson program at RHIC to constrain the proton's helicity parton distributions. Our calculation enables a very fast and efficient numerical computation of the relevant spin asymmetries at RHIC, which is an important ingredient for the inclusion of RHIC data in a global analysis of nucleon helicity structure. We confirm the validity of our calculation by comparing with an existing code that treats the next-to-leading order cross sections entirely numerically by Monte-Carlo integration techniques. We also provide new comparisons of the present RHIC data with results for some of the sets of polarized parton distributions available in the literature.

13 pages, 6 figures. Updated figure for comparison to RHIC data. Version to appear in Phys. Rev. D

References in corpus (12)

• Parton distributions for the LHC
• Extraction of Spin-Dependent Parton Densities and Their Uncertainties
• A first unbiased global determination of polarized PDFs and their uncertainties
• Evidence for polarization of gluons in the proton
• Global Analysis of Helicity Parton Densities and Their Uncertainties
• Mixed QCD-electroweak O(α_sα) corrections to Drell-Yan processes in the resonance region: pole approximation and non-factorizable corrections
• Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC
• Cross Section and Parity Violating Spin Asymmetries of W^+/- Boson Production in Polarized p+p Collisions at sqrt(s)=500 GeV
• Measurement of the parity-violating longitudinal single-spin asymmetry for $W^{\pm }$ boson production in polarized proton-proton collisions at $\sqrt{s}=500$GeV
• Threshold Resummation for W-Boson Production at RHIC
• Helicity Parton Distributions from Spin Asymmetries in W-Boson Production at RHIC
• Low-mass lepton pair production at large transverse momentum

Cited by in corpus (8)

• Polarized Antimatter in the Proton from Global QCD Analysis
• Isovector EMC effect from global QCD analysis with MARATHON data
• Expansion by regions meets angular integrals
• Asymptotic behavior of angular integrals in the massless limit
• Angular integrals with three denominators via IBP, mass reduction, dimensional shift, and differential equations
• Effect of sea quarks on the single-spin asymmetries $A_L^{W^{\pm }}$ in polarized pp collisions at RHIC
• On multi-propagator angular integrals
• Bayesian Monte Carlo extraction of sea asymmetry with SeaQuest and STAR data