Measurements of the B-meson semileptonic branching fraction

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1990

OSTI ID:5225104

Worris, M A

The author has made a precision measurement of the B meson semileptonic branching fraction at the {Upsilon}(4S) resonance using data from the CLEO detector at the Cornell Electron Storage Ring. The inclusive electron and muon spectra are fit to radiatively corrected theoretical models to extract the branching fraction. Using the model of Altarelli et al., he finds B({bar B} {yields} X{ell}{sup {minus}}{bar {nu}}) = 10.5 {plus minus} 0.2 {plus minus} 0.4. The form-factor models of Isgur et al., and Wirbel et al. yield poor fits to the data when fit below 1.8 GeV/c. Using a modified version of the model of Isgur et al., in which the contribution of D{sup {asterisk}{asterisk}}{ell}{sup {minus}}{bar {nu}} is allowed to vary, he obtains B({bar B} {yields} X{ell}{sup {minus}}{bar {nu}}) = 11.2 {plus minus} 0.3 {plus minus} 0.4, in a substantially improved fit. He interprets this result as evidence for high mass charm contributions to the lepton spectrum unaccounted for by form-factor models. The average of the Altarelli fit with the modified Isgur fit yields B({bar B} {yields} X{ell}{sup {minus}}{bar {nu}}) = 10.8 {plus minus} 0.2 {plus minus} 0.4 {plus minus}0.4, where the errors are due to statistics, systematics, and model dependence. He has used the ratio of leptons to dilepton events at the {Upsilon}(4S) to attempt to reduce the dependence on the assumption of negligible non-B{bar B} production. The results are in agreement with the fits to the inclusive spectrum, though the former have larger statistical and systematic errors. He concludes that the effect of non-B{bar B} decays on the B meson branching fraction is small of those decays do not have a significant lepton contribution.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• OSTI ID: 5225104
• Country of Publication: United States
• Language: English

Related Subjects

662350* -- Decays of Mesons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BEAUTY MESONS
BEAUTY PARTICLES
BOSONS
BOTTOMONIUM
BRANCHING RATIO
CESR STORAGE RING
CORRECTIONS
DECAY
ELEMENTARY PARTICLES
ERRORS
FERMIONS
FORM FACTORS
HADRONS
LEPTONS
MATHEMATICAL MODELS
MESONS
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PROPERTIES
QUARKONIUM
RADIATIVE CORRECTIONS
SEMILEPTONIC DECAY
SPECTRA
STORAGE RINGS
VECTOR MESONS
WEAK PARTICLE DECAY