Hard photon processes in electron-positron annihilation at 29 GeV

Technical Report · Sat Nov 01 00:00:00 EST 1986

DOI:https://doi.org/10.2172/7059641· OSTI ID:7059641

Gold, M S

The hard photon processes ..mu mu gamma.. and hadrons + ..gamma.. in e/sup +/e/sup -/ annihilation at 29 GeV have been studied. The study is based on an integrated luminosity of 226 pb/sup -1/ taken at PEP with the Mark II detector. For the ..mu mu gamma.. process, a small fraction of non-planar events are observed with missing momentum along the beam direction. The resulting missing energy spectrum is consistent with that expected from higher order effects. The observed cross section is consistent with the predicted cross section for this process, sigma/sup exp/sigma/sup th/ = .90 +- .05 +- .06. The observed hard photon energy spectrum and mass distributions are found to be in agreement with O(..cap alpha../sup 3/) QED. The measured charge asymmetry is in good agreement with the predicted value, A/sub exp/A/sub th/ = .83 +- .25 +- .12. The ..mu gamma.. invariant mass distribution is used to place a limit on a possible excited muon coupling G..gamma../M* for excited muon masses in the range 1 < M* < 21 GeV of (G..gamma../M*)/sup 2/ < 10/sup -5/ GeV/sup -2/ at a 95% confidence level. In the hadrons + ..gamma.. process, evidence for final state radiation is found in an excess of events over that predicted from initial state radiation alone of 253 +- 54 +- 60 events. Further evidence for final state radiation is found in a large hadronic charge asymmetry A/sub Had+..gamma../= (-24.6 +- 5.5)%.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7059641
• Report Number(s): LBL-22433; ON: DE87006248
• Resource Relation: Other Information: Thesis. Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ELECTRON-POSITRON INTERACTIONS
ANNIHILATION
ASYMMETRY
FINAL-STATE INTERACTIONS
GEV RANGE 10-100
HADRONS
MUONS
PEP STORAGE RINGS
PHOTONS
QUANTUM ELECTRODYNAMICS
REST MASS
BASIC INTERACTIONS
ELECTRODYNAMICS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
FIELD THEORIES
GEV RANGE
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
LEPTONS
MASS
MASSLESS PARTICLES
PARTICLE INTERACTIONS
QUANTUM FIELD THEORY
STORAGE RINGS
645101* - High Energy Physics- Particle Interactions &amp; Properties-Experimental- Electromagnetic Interactions &amp; Properties