A study of the polarization and decay of the tau lepton at L3

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7042178

Bao, J

A study with e[sup +]e[sup [minus]] [yields] [tau][sup +][tau][sup [minus]] events collected at the Z[sup 0] resonance with the L3 detector at LEP has been carried out. From approximately 10,000 [tau]-pair events, the leptonic decay branching ratios of the [tau] lepton are measured to be: Br([tau] [yields] ev[bar v]) = 0.1772 [+-] 0.0036[sup +0.0041][sub [minus]0.0037], Br([tau] [yields] [mu]v[bar v]) = 0.1760 [+-] 0.0039[sup +0.0039][sub [minus]0.0036]. The longitudinal polarization asymmetry of the tau is measured in the decay [tau] [yields] ev[bar v] by fitting the electron energy spectrum to the expected theoretical distribution from the Standard Model. The polarization is found to be: A[sub pol] = [minus]0.096 [+-] 0.091 [+-] 0.066, which corresponds to a value of the electroweak mixing angle sin[sup 2][theta][sub w] = 0.238 [+-] 0.011 [+-] 0.008, in good agreement with other measurements of sin[sup 2][theta][sub w] and the prediction from the Standard Model for electroweak interactions.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• OSTI ID: 7042178
• Country of Publication: United States
• Language: English

Related Subjects

662370* -- Decays of Leptons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BASIC INTERACTIONS
DECAY
ELECTRON SPECTRA
ELEMENTARY PARTICLES
FERMIONS
HEAVY LEPTONS
INTERACTIONS
LEPTONIC DECAY
LEPTONS
MATHEMATICAL MODELS
PARTICLE DECAY
PARTICLE MODELS
POLARIZATION-ASYMMETRY RATIO
POSTULATED PARTICLES
SPECTRA
STANDARD MODEL
TAU PARTICLES
UNIFIED GAUGE MODELS
WEAK INTERACTIONS
WEAK PARTICLE DECAY