Measurement of the $\bar{B} \rightarrow X_s γ$ Branching Fraction with a Sum of Exclusive Decays
hep-ex
/ Authors
Belle Collaboration, T. Saito, A. Ishikawa, H. Yamamoto, A. Abdesselam, I. Adachi, H. Aihara, S. Al Said, K. Arinstein, D. M. Asner
and 172 more authors
T. Aushev, R. Ayad, A. M. Bakich, V. Bansal, B. Bhuyan, A. Bobrov, A. Bondar, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, D. Červenkov, A. Chen, B. G. Cheon, K. Chilikin, K. Cho, V. Chobanova, S. -K. Choi, Y. Choi, D. Cinabro, J. Dalseno, M. Danilov, J. Dingfelder, Z. Doležal
/ Abstract
We use 772$\times 10^6$ $B \bar{B}$ meson pairs collected at the $Υ(4S)$ resonance with the Belle detector to measure the branching fraction for $\bar{B} \rightarrow X_s γ$. Our measurement uses a sum-of-exclusives approach in which 38 of the hadronic final states with strangeness equal to $+1$, denoted by $X_s$, are reconstructed. The inclusive branching fraction for $M_{X_s}<$ 2.8 GeV/$c^2$, which corresponds to a minimum photon energy of 1.9 GeV, is measured to be ${\cal B}(\bar{B} \rightarrow X_s γ)=(3.51\pm0.17\pm0.33)\times10^{-4}$, where the first uncertainty is statistical and the second is systematic.