Search for structure in radiative e/sup +/e/sup -/ annihilation using photon tagging

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5484474

White, J T

The radiative annihilation reaction, e/sup +/e/sup -/ ..-->.. ..gamma..X, has been investigated, where X = ..mu../sup +/..mu../sup -/, q anti-q, or low multiplicity tau/sup +/tau/sup -/-like final states. The data was collected by the Two-Photon experiment of the 2..gamma../TPC collaboration at the PE e/sup +/e/sup -/ storage ring at SLAC. The e/sup +/e/sup -/ c.m. energy was 29 GeV with an integrated luminosity of 37 pb/sup -1/. By detecting (tagging) an energetic photon at small angles from the beam direction (24 ..-->.. 90 mr) in coincidence with hadrons or muons at wider angles, it was possible to obtain a clean sample of initial-state radiative events. The energy of the small-angle photon was measured in one of the NaI arrays of the Two-Photon experiment, hadrons were identified in the TPC, and muons were identified in both the central and forward muon chambers. The number of events and general shape of all spectra were found to be in good agreement with the QED and QCD expectations. The ratio of the hadronic cross section to the muon cross section, R, was measured to be approximately constant with a value of 4.07 +/- 0.38 averaged over the mass range from 5 to 25 GeV. A possible excess of events was observed at a mass value near 22 GeV in all spectra. The spectrum obtained by summing the three categories, but requiring at least one muon candidate in the decay debris, exhibits an excess at 22 GeV with a statistical fluctuation probability of approx. =10/sup -5/. However, using results from the zero-tagged ..mu../sup +/..mu../sup -/ study and considering other details, the excess does not appear to be consistent with radiative annihilation resonance production.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 5484474
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ELECTRON-POSITRON INTERACTIONS
PAIR PRODUCTION
HADRONS
MULTIPLE PRODUCTION
MUON PAIRS
PHOTONS
PARTICLE PRODUCTION
TAU PARTICLES
CROSS SECTIONS
EXPERIMENTAL DATA
GEV RANGE 10-100
MASS SPECTRA
PEP STORAGE RINGS
TAGGED PHOTON METHOD
COINCIDENCE METHODS
COUNTING TECHNIQUES
DATA
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GEV RANGE
HEAVY LEPTONS
INFORMATION
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
LEPTONS
MASSLESS PARTICLES
NUMERICAL DATA
PARTICLE INTERACTIONS
POSTULATED PARTICLES
SPECTRA
STORAGE RINGS
645101* - High Energy Physics- Particle Interactions & Properties-Experimental- Electromagnetic Interactions & Properties