Anomalous electron--muon and electron--hadron production in electron--positron annihilation. [Branching ratio lh → charged hadron + 2ν, ν + nγ, τ → ν_τ e^-ν_e^-, ν_τ μν_μ, rare modes, cross sections; Thesis]

Technical Report · Sat Apr 01 04:00:00 EST 1978

DOI:https://doi.org/10.2172/6778585· OSTI ID:6778585

Kwan, Betty Puifun ^[1]

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1. Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Results of studies of anomalous electron-muon and electron-hadron events produced in electron-positron annihilation are presented. The data for this work were obtained with a lead-glass counter system, which was added to one octant of the Stanford Linear Accelerator Center-Lawrence Berkeley Laboratory magnetic detector at the electron-positron storage ring SPEAR. The lead-glass counter system provides good electron identification for part of the magnetic detector. The events under study have two detected charged particles and any number of detected photons. One detected charged particle is identified as an electron in the lead-glass counter system. The other detected charged particle is identified as a muon or hadron in the magnetic detector. Anomalous events are events which are not subject to conventional explanations; examples of conventional explanations are misidentification of particles or the decay of ordinary or strange hadrons. These data confirm previous observations of anomalous lepton production at SPEAR and DESY. The data corrected for charm background are consistent with heavy lepton production and decay. The branching ratio for the heavy lepton to decay into an electron and two neutrinos was measured to be 0.21 +- 0.05. The branching ratio for the heavy lepton to decay into one charged hadron, one neutrino and any number of photons was measured to be 0.28 +- 0.13. They are consistent with the theoretical values within the errors.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-03-0515
• OSTI ID: 6778585
• Report Number(s): SLAC-207; SLAC--207
• Country of Publication: United States
• Language: English

Related Subjects

645101* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Electromagnetic Interactions & Properties
645102 -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
BASIC INTERACTIONS
BRANCHING RATIO
CROSS SECTIONS
DECAY
ELECTROMAGNETIC INTERACTIONS
ELECTRON-MUON INTERACTIONS
ELECTRON-NUCLEON INTERACTIONS
ELECTRON-POSITRON INTERACTIONS
ELECTROPRODUCTION
ELEMENTARY PARTICLES
FERMIONS
HEAVY LEPTONS
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-LEPTON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
LEPTONIC DECAY
LEPTONS
MASS
MASSLESS PARTICLES
NEUTRINOS
PAIR PRODUCTION
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
POSTULATED PARTICLES
SEMILEPTONIC DECAY
TAU NEUTRINO
TAU PARTICLE
WEAK INTERACTIONS
WEAK PARTICLE DECAY