ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2008, vol. 101, p. -
Measurement of branching fractions, isospin, and CP-violating asymmetries for exclusive b→dγ modes
We report new measurements of the decays B+→ρ+γ, B0→ρ0γ, and B0→ωγ using a data sample of 657×106 B meson pairs accumulated with the Belle detector at the KEKB e+e- collider. We measure branching fractions B(B+→ρ+γ)=(8.7-2.7-1. 1+2.9+0.9)×10-7, B(B0→ρ0γ)=(7.8-1.6-1.0+1.7+0.9)×10- 7, and B(B0→ωγ)=(4.0-1.7+1.9±1.3)×10-7. We also report the isospin asymmetry Δ(ργ)=-0.48-0.19-0.09+0.21+0.08 and the first measurement of the direct CP-violating asymmetry ACP(B+→ρ +γ)=-0.11±0.32±0.09, where the first and second errors are statistical and systematic, respectively. © 2008 The American Physical Society.