Cross Section and Parity-Violating Spin Asymmetries of W{sup {+-}} Boson Production in Polarized p+p Collisions at {radical}(s)=500 GeV

• Published in: Physical review letters Vol. 106; no. 6
• Main Authors: Adare, A., Kinney, E., Linden Levy, L. A., Nagle, J. L., Wysocki, M., Afanasiev, S., Isupov, A., Litvinenko, A., Malakhov, A., Peresedov, V., Rukoyatkin, P., Zolin, L., Aidala, C., Brooks, M. L., Butsyk, S., Guo, L., Jiang, X., Kapustinsky, J., Kunde, G. J., Lee, D. M.
• Format: Journal Article
• Language: English
• Published: United States 11-02-2011
• Subjects: ACCELERATORS; ANGULAR MOMENTUM; ANTILEPTONS; ANTIMATTER; ANTIPARTICLES; ASYMMETRY; BARYON-BARYON INTERACTIONS; BOSONS; BROOKHAVEN RHIC; CHARGED PARTICLES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COLLISIONS; CROSS SECTIONS; D QUARKS; DECAY; ELECTRON NEUTRINOS; ELECTRONS; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; GEV RANGE; GEV RANGE 100-1000; HADRON-HADRON INTERACTIONS; HEAVY ION ACCELERATORS; INTERACTIONS; IONS; LEPTONS; LINEAR MOMENTUM; MASS; MASSLESS PARTICLES; MATTER; NEUTRINOS; NUCLEON-NUCLEON INTERACTIONS; PARITY; PARTICLE INTERACTIONS; PARTICLE PRODUCTION; PARTICLE PROPERTIES; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; POSITRONS; PROTON-NUCLEON INTERACTIONS; PROTON-PROTON INTERACTIONS; QUARKS; SPIN; STORAGE RINGS; TRANSVERSE MOMENTUM; TUNGSTEN IONS; U QUARKS
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PHYSREVLETT.106.062001

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)xBR(W{sup +}{yields}e{sup +}{nu}{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)xBR(W{sup -}{yields}e{sup -}{nu}{sub e})=31.7{+-}12.1(stat){sub -8.2}{sup +10.1}(syst){+-}4.8(norm) pb.