Measurements of tau lepton production and decay at. sqrt. s = 29 GeV

Thesis/Dissertation · Tue Dec 31 23:00:00 EST 1985

OSTI ID:6594563

Read, A L

Properties of the tau lepton were measured in data taken with the MAC detector at the PEP e/sup +/e/sup -/ storage ring at the Stanford Linear Accelerator Center. Approximately 27000 tau-pair events were produced at a center of mass energy of 29 GeV and about half of these were selected from the data in order to study various properties of the tau. Precise measurements of the leptonic branching ratios of the tau yielded B(tau ..-->.. nu/sub tau/e antinu/sub e/) = 0.174 +/- 0.008 +/- 0.005 and B(tau ..-->.. nu/sub tau/..mu..antinu/sub ..mu../) = 0.177 +/- 0.008 +/- 0.005. A precise measurement of the pion branching ratio yielded B(tau..-->.. nu/sub tau/..pi..) = 0.106 +/- 0.004 +/- 0.008. A search for tau decays into five charged hadrons was performed and an upper limit on the branching ratio for this decay mode was set at 0.0027 at the 95% confidence level. The Michel parameter was measured with the leptonic energy spectra and was found to be 0.79 +/- 0.11 +/- 0.09, consistent with the V-A hypothesis for the tau nu/sub tau/ - W vertex. Measurements of the coupling constants of the tau to the weak neutral current were made by observation of the forward-backward energy asymmetry of the tau decay products and their average energy. These measurements yielded g/sub a//sup e/g/sub v//sup tau/ = (0.26 +/- 0.31) x (1 +/- 0.012) and g/sub v//sup e/g/sub a//sup tau/ = (-0.05 +/- 0.21 +/- 0.34) respectively, consistent with the Glashow-Weinberg-Salam model of electroweak interactions.

• Research Organization: Colorado Univ., Boulder (USA)
• OSTI ID: 6594563
• Country of Publication: United States
• Language: English

Related Subjects

645102* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
ANTILEPTONS
ANTIMATTER
ANTINEUTRINOS
ANTIPARTICLES
ASYMMETRY
BASIC INTERACTIONS
BOSONS
BRANCHING RATIO
COUPLING CONSTANTS
CURRENTS
DATA
DECAY
ELECTRON-POSITRON INTERACTIONS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
EXPERIMENTAL DATA
FERMIONS
FIELD THEORIES
GEV RANGE
GEV RANGE 10-100
HADRONS
HEAVY LEPTONS
INFORMATION
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
LEPTONIC DECAY
LEPTONS
MASSLESS PARTICLES
MATHEMATICAL MODELS
MESONS
NEUTRAL CURRENTS
NEUTRINOS
NUMERICAL DATA
PAIR PRODUCTION
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PEP STORAGE RINGS
PIONS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
SEMILEPTONIC DECAY
SPECTRA
STORAGE RINGS
TAU NEUTRINOS
TAU PARTICLES
UNIFIED GAUGE MODELS
UNIFIED-FIELD THEORIES
WEAK INTERACTIONS
WEAK NEUTRAL CURRENTS
WEAK PARTICLE DECAY
WEINBERG-SALAM GAUGE MODEL