Cross Section and Parity Violating Spin Asymmetries of W plus or minus Boson Production in Polarized p+p Collisions at s=500 GeV
- University of Colorado, Boulder
- ORNL
- University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
- Oak Ridge National Laboratory (ORNL)
- University of Tennessee, Knoxville (UTK)
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 +} {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) x BR(W{sup -} {yields} e{sup -} {bar {nu}}{sub e}) = 31.7 {+-} 12.1(stat){sub -8.2}{sup +10.1}(syst) {+-} 4.8(norm) pb.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1004969
- Journal Information:
- Physical Review Letters, Vol. 106, Issue 6; ISSN 0031--9007
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cross Section and Parity-Violating Spin Asymmetries of W{sup {+-}} Boson Production in Polarized p+p Collisions at {radical}(s)=500 GeV
Extraction of the width of the W boson from measurements of {sigma}(pp(bar sign){yields}W+X)xB(W{yields}e{nu}) and {sigma}(pp(bar sign){yields}Z+X)xB(Z{yields}ee) and their ratio