Observation of B- /- -> X-c1 pi( /-) and search for direct CP violation
R Kumar, JB Singh, K Abe, K Abe, H Aihara, D Anipko, T Aushev, T Aziz, AM Bakich, V Balagura, M Barbero, A Bay, I Bedny, K Belous, U Bitenc, S Blyth, A Bozek, M Bracko, TE Browder, M-C Chang Show all
PHYSICAL REVIEW D | AMER PHYSICAL SOC | Published : 2006
We report the first observation of B±→χc1π±, a Cabibbo- and color-suppressed decay in a data sample of 386×106 BB̄ events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe 55±10 signal events with a statistical significance of 6.3σ including systematic uncertainties. The measured branching fraction and charge-asymmetry is B(B±→χc1π ±)=(2.2±0.4±0.3)×10-5 and Aπ=0.07±0. 18±0.02, respectively. We also determine the ratio B(B±→χ c1π±)/B(B±→χc1K±)=(4.3±0.8±0.3)%. © 2006 The American Physical Society.