Measurement of the polarized forward-backward asymmetry of Z{sup 0} {yields} b{bar b} using a lifetime tag and momentum-weighted track charge
We present a direct measurement of the parity-violating parameter A{sub b} by analyzing the left-right forward-backward asymmetry of b quarks in e{sup +}e{sup {minus}} {yields} Z{sup o} {yields} b{bar b}. The SLD experiment observes hadronic decays of Z{sup o} bosons produced at resonance in collisions of longitudinally polarized electrons and unpolarized positrons at the SLC. Heavy flavor decays of the Z{sup o} are identified by taking advantage of the long lifetime of B hadrons, the small, stable SLC beam spot, and precise tracking from SLD. The asymmetry A{sub b} is measured with a self-calibrating technique employing momentum-weighted track charge from both hemispheres in the tagged events. From our 1994--1995 sample of 3.6 pb{sup {minus}1} of e{sup +}e{sup {minus}} annihilation data with a luminosity-weighted average e{sup {minus}} polarization of 77.3%, and our 1993 sample of 1.8 pb{sup {minus}1} with a luminosity-weighted polarization of 63.1%, we obtain A{sub b}(preliminary) = 0.843 {plus_minus} 0.046(stat.) {plus_minus} 0.051(syst.).
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 148612
- Report Number(s):
- SLAC-PUB-95-6979; CONF-950705-34; ON: DE96002433; TRN: 96:001331
- Resource Relation:
- Conference: HEP 95: international Europhysics conference on high-energy physics, Brussels (Belgium), 27 Jul - 2 Aug 1995; Other Information: PBD: Aug 1995
- Country of Publication:
- United States
- Language:
- English
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