Cross Section and Parity-Violating Spin Asymmetries of W± Boston Production in Polarized p + p Collisions at √sNN = 500 GeV
Large parity-violating longitudinal single-spin asymmetries A{sub L}{sup e+} = -0.86{sub -0.14}{sup +0.30} and A{sub L}{sup e-} = 0.88{sub -0.71}{sup +0.12} are observed for inclusive high transverse momentum electrons and positrons in polarized p+p collisions at a center-of-mass energy of {radical}s = 500 GeV with the PHENIX detector at RHIC. These e{sup {+-}} come mainly from the decay of W{sup {+-}} and Z{sup 0} bosons, and their asymmetries directly demonstrate parity violation in the couplings of the W{sup {+-}} to the light quarks. The observed electron and positron yields were used to estimate W{sup {+-}} boson production cross sections for the e{sup {+-}} channels of {sigma}(pp {yields} W{sup +}X) x BR(W{sup +} e{sup +}v{sub e}) 144.1 {+-} 21.2(stat){sub -10.3}{sup +3.4}(syst) {+-} 21.6(norm) pb, and {sigma}(pp {yields} W{sup -}X) x BR(W{sup -} {yields} e{sup -}v{sup -}) = 31.7 {+-} 12.1(stat){sub -8.2}{sup +10.1}(syst) {+-} 4.8(norm) pb.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1019478
- Report Number(s):
- BNL-94979-2011-JA; PRLTAO; R&D Project: PO 003; KB0201021; TRN: US1103635
- Journal Information:
- Physical Review Letters, Vol. 106, Issue 6; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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