Search for B --> Mu Anti-Muon-Neutrino Gamma and B --> e Anti-Electron-Neutrino Gamma

摘要

We have searched for the decays B(yields)(mu)(bar (nu))(sub(mu))(gamma) and B (yields) e(bar(nu)) (sub e)(gamma) in a sample of 2.7 million charged B decays collected with the CLEO II detector. In the muon channel, we observe no candidates in the signal region and set an upper limit on the branching fraction of(Beta)(B(yields)(mu) (bar(nu))(sub(mu))(gamma))< 5.2 x 10(sup -5) at the 90% confidence level. In the electron channel, we observe 5 candidates in the signal region and set an upper limit on the branching fraction of(Beta)(B(yields)) e(bar(nu)((sub e)(gamma))< 2.0 x 10(sup -4)at the 90% confidence level.