A Preliminary Direct Measurement of the Parity-Violating Coupling of the Z{sup 0} to Strange Quarks, A{sub s}
We present an updated direct measurement of the parity-violating coupling of the Z{sup 0} to strange quarks, A{sub s}, derived from the full SLD data sample of approximately 550,000 hadronic decays of Z{sup 0} bosons produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1998. Z{sup 0} {r_arrow} s{bar s} events are tagged by the presence in each event hemisphere of a high-momentum K{sup {+-}}, K{sub s} or {Lambda}{sup 0}/{bar {Lambda}}{sup 0} identified using the Cherenkov Ring Imaging Detector and/or a mass tag. The CCD vertex detector is used to suppress the background from heavy-flavor events. The strangeness of the tagged particle is used to sign the event thrust axis in the direction of the initial s quark. The coupling A{sub s} is obtained directly from a measurement of the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. The background from u{bar u} and d{bar d} events is measured from the data, as is the analyzing power of the method for s{bar s} events. We measure: A{sub s} = 0.85 {+-} 0.06(stat.) {+-} 0.07(syst.)(preliminary).
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 10084
- Report Number(s):
- SLAC-PUB-8154; TRN: US0103346
- Resource Relation:
- Other Information: PBD: 9 Jul 1999
- Country of Publication:
- United States
- Language:
- English
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