Observation of B -> p(-)Lambda gamma
YJ Lee, MZ Wang, K Abe, K Abe, H Aihara, Y Asano, V Aulchenko, T Aushev, S Bahinipati, AM Bakich, I Bedny, U Bitenc, I Bizjak, A Bondar, A Bozek, M Bracko, J Brodzicka, TE Browder, MC Chang, P Chang Show all
PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2005
We report the first observation of the radiative hyperonic B decay B+ --> plambdagamma, using a 140 fb(-1) data sample recorded on upsilom(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured branching fraction is [symbol: see text](B+ --> plambdagamma) = (2.16(+0.58)(-0.53) +/- 0.20) x 10(-6). We examine its M(plambda) distribution and observe a peak near threshold. This feature is expected by the short-distance b --> sgamma transition. A search for B+ --> pepsilon0gamma yields no significant signal, and we set a 90% confidence-level upper limit on the branching fraction of [symbol: see textB+ --> pepsilon0gamma <4.6 x 10(-6).