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Abstract:

The ratio of charged and neutral B meson production at the γ(4S), f+-/f00, is measured through the decays B̄→D*ℓ^-ν̄ℓ, reconstructed using a partial reconstruction method where the D* is detected only through a pion daughter from the decay D*→Dπ. Using data collected by the CLEO II detector, the charged and neutral B decays are measured in such a way that their ratio is independent of the decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This measurement yields the ratio of production fractions times the ratio of semileptonic branching fractions, f+-b+/f 00b0. Assuming that b+/b0 is equal to the lifetime ratio τ+/τ0 and using the world average value of τ+/τ0 as input, we obtain f +-/f00= 1.058±0.084±0.136. © 2002 The American Physical Society.

Abstract:

We present new measurements of branching fractions for the color-favored decays B+ → D0π- and B̄0 → D+π-. Using 9.67×106 BB̄ pairs collected with the CLEO detector, we obtain the branching fractions Β(B- → D0π - = (49.7±1.2±2.9±2.2)×104 and Β(B̄0 → D+π-) = (26.8±1.2±2.4±1.2)×10-4. The first error is statistical, the second is systematic, and the third is due to the experimental uncertainty on the production ratio of charged and neutral B mesons in Y(4S) decays. These results, together with the current world average for the color-suppressed branching fraction Β(B̄+ → D 0π0), are used to determine the cosine of the strong phase difference δI between the I = 1/2 and I=3/2 isospin amplitudes. We find cos δI = 0.863 -0.023-0.035-0.030+0.024+0.036+0.038, and obtain a 90% confidence interval of 16.5° < δI < 38.1°. This nonzero value of δI suggests the presence of final state interactions in the D π system. © 2002 The American Physical Society.

Abstract:

We have searched for lepton flavor violating decays of the Ï„ lepton with one or two KS⁰ mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 13.9 fb^-1 at the Y (4S) resonance. No evidence for signals were found; therefore, we have set 90% confidence level (C.L.) upper limits on the branching fractions Î’(Ï„^- → e^- K S⁰)<9.1×10^-7, Î’(Ï„^- →μ^- KS⁰)<9.5×10^-7, Î’(Ï„^- → e^-KS⁰K S⁰) <2.2× 10^-6, and Î’(Ï„^- → μ^- KS⁰K S⁰)<3.4×10^-6. These represent significantly improved upper limits on the two-body decays and first upper limits on the three-body decays. © 2002 The American Physical Society.

Abstract:

We have performed a search for radiative 6-hadron decays using events produced in ppÌ… collisions at √s=1.8TeV and collected by the Collider Detector at Fermilab. The decays we considered were B^0Ì…d→K^*0(→K^-Ï€⁺γ, B^0Ì…s→φ(→K⁺K^-)γ,⁰b→γ(→p03°ä0^-)γ), and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external photon conversion before the tracking detector volume. By combining the two methods we obtain upper limits on the branching fractions for the B^0Ì…d, B^0Ì…s and γ,⁰b radiative decays which, at the 95% confidence level, are found to be B(B^0Ì…d→K^*0γ<1.4×^-4,B(B^0Ì…d→ϵ¥³)<1.6×^-4,and (γ,⁰b→γγ)<1.9×^-3.