Determination of electroweak parameters at the SLC

Conference · Sun Sep 01 04:00:00 EDT 1996

OSTI ID:484565

Torrence, E

We present an improved measurement of the left-right cross section asymmetry (A{sub LR}) for Z{sup 0} boson production by e{sup +}e{sup -} collisions. The measurement was performed at a center-of-mass energy of 91.28 GeV with the SLD detector at the SLAC Linear Collider (SLC) during the 1994-95 running period. The luminosity-weighted average polarization of the SLC electron beam during this run was measured to be (77.23 {+-} 0.52)%. Using a sample of 93,644 hadronic Z{sup 0} decays, we measure the pole asymmetry A{sub LR}{sup 0} to be 0.1512 {+-} 0.0042(stat.) {+-} 0.0011(syst.) which is equivalent to an effective weak mixing angle of sin{sup 2} {theta}{sub W}{sup eff} = 0.23100 {+-} 0.00054(stat.) {+-} 0.00014(syst.). We also present a preliminary direct measurement of the Z{sup 0}-lepton coupling asymmetries A{sub e}, A{sub {mu}}, and A{sub {tau}} extracted from the differential cross section observed in leptonic Z{sup 0} decays. We combine these results with our previous A{sub LR} measurement to obtain a combined determination of the weak mixing angle sin{sup 2} {theta}{sub W}{sup eff} = 0.23061 {+-} 0.00047.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States); Science and Engineering Research Council, Swindon (United Kingdom); Istituto Nazionale di Fisica Nucleare, Rome (Italy); US-Japan High Energy Physics Collaboration
• DOE Contract Number: AC03-76SF00515; FG02-91ER40676; FG03-91ER40618; FG03-92ER40689; FG03-93ER40788; FG02-91ER40672; FG02-91ER40677; AC03-76SF00098; FG02-92ER40715; AC02-76ER03069; FG06-85ER40224; FG05-91ER40627; FG02-95ER40896; FG02-92ER40704
• OSTI ID: 484565
• Report Number(s): SLAC-PUB--7307; CONF-960765--55; ON: DE97007491; CNN: NSF Grant PHY-91-13428; NSF Grant PHY-89-21320; NSF Grant PHY-92-04239; NSF Grant PHY-88-17930; NSF Grant PHY-88-19316; NSF Grant PHY-92-03212
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CROSS SECTIONS
ELECTRON-POSITRON INTERACTIONS
HADRONIC PARTICLE DECAY
PARTICLE PRODUCTION
POLARIZATION-ASYMMETRY RATIO
STANFORD LINEAR COLLIDER DETECTOR
WEINBERG ANGLE
Z NEUTRAL BOSONS