Prompt electron production in electron-positron annihilations at 29 GeV

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5645253

Koop, D E

The production of prompt electrons in high statistics sample (118 pb/sup -1/) of multihadron events produced in electron positron annihilations at 29 Gev has been studied. The experiment was performed using the DELCO facility on the PEP storage ring at SLAC. Electron identification was done primarily with a large acceptance threshold Cherenkov counter. Both the momentum and the transverse momentum spectra are measured in terms of a differential cross section for electrons having momenta in the range 0.5 < P < 5.5 GeV/c. The inclusive cross section in this momentum range are 35.8 +/- 3.1 pb. The final distribution of candidates in the P - P/sub perpendicular/ plane are fit well using a Monte Carlo having a combination of bottom and charm quark decays with the semielectronic branching ratios of (15.0 +/- 2.9)% and (8.9 +/- 1.4)%. No evidence of electron production from new sources has been observed and a cross section upper limit of 11.6 pb (90% CL) for this process has been determined. The fragmentation functions are hard for both b and c quarks, characterized by the values = 0.77 + 0.05 and = 0.68 +/- 0.06, where z is the fraction of the heavy quark's energy that is retained by the primary hadron containing the heavy quark. Events having two electrons with an inclusive cross section of 2.8 +/- 1.3 pb for this process are observed, which is consistent with the rate expected from the measured semielectronic rates.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 5645253
• Country of Publication: United States
• Language: English

Related Subjects

645102* -- High Energy Physics-- Particle Interactions &amp; Properties-Experimental-- Weak Interactions &amp; Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
B MESONS
BOSONS
BRANCHING RATIO
CHARM PARTICLES
CROSS SECTIONS
DATA
DECAY
DIFFERENTIAL CROSS SECTIONS
ELECTRON-POSITRON INTERACTIONS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
EXPERIMENTAL DATA
FERMIONS
GEV RANGE
GEV RANGE 10-100
HADRONS
INFORMATION
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
LEPTONS
LINEAR MOMENTUM
MESONS
MONTE CARLO METHOD
MULTIPLE PRODUCTION
NUMERICAL DATA
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PEP STORAGE RINGS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
QUARKS
SEMILEPTONIC DECAY
STORAGE RINGS
TRANSVERSE MOMENTUM
WEAK PARTICLE DECAY