We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 → D*- l+v̄. This spectrum, measured with 2.38 fb-1 of data collected at the Y(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Y(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B+ and B0 pairs at the Y(4S). We report b+/b0 = 0.950+0.117-0.080 ± 0.091, b0 = (10.78 ± 0.60 ± 0.69)%, and b+ = (10.25 ± 0.57 ± 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, τ+/τ0.
|Original language||English (US)|
|Number of pages||8|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - May 1 1997|
ASJC Scopus subject areas
- Nuclear and High Energy Physics