Investigation of Semileptonic $B$ Meson Decay to P-Wave Charm Mesons

TL;DR

This study measures specific semileptonic B meson decay rates involving P-wave charm mesons, revealing that a significant portion of B decays remains unaccounted for by observed exclusive channels.

Contribution

First measurement of certain semileptonic B decay branching fractions involving P-wave charm mesons using CLEO II data, providing new insights into B decay mechanisms.

Findings

Measured Br(B^- -> D_1^0 l^- ar{ u}) x Br(D_1^0 -> D^{*+}\pi^-) = (0.373 ± 0.085 ± 0.052 ± 0.024)%

Set an upper limit for Br(B^- -> D_2^{*0} l^- ar{ u}) x Br(D_2^{*0} -> D^{*+}\pi^-) < 0.16% (90% C.L.)

At least 20% of B^- semileptonic decays are unaccounted for by observed exclusive channels.

Abstract

We have studied semileptonic $B$ meson decays with a P-wave charm meson in the final state using 3.29 x 10^6 B\bar{B} events collected by the CLEO~II detector at the Cornell Electron-positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction: Br(B^- -> D_1^0 l^- \bar{\nu}) x Br(D_1^0 -> D^{*+}\pi^-) = (0.373 \pm 0.085 \pm 0.052 \pm 0.024)% and an upper limit for Br(B^- -> D_2^{*0} l^- \bar{\nu}) x Br(D_2^{*0} -> D^{*+}\pi^-) < 0.16%$ (90% C.L.). These results indicate that at least 20% of the total B^- semileptonic rate is unaccounted for by the observed exclusive decays, B^- -> D^0 l^- \bar{\nu}, B^- -> D^{*0} l^- \bar{\nu}, B^- -> D_1^0 l^- \bar{\nu}, and B^- -> D_2^{*0} l^- \bar{\nu}.