Implication of the Β → (ρ, ω) γ branching ratios for the CKM phenomenology

We study the implication of the recent measurement by the BELLE collaboration of the averaged branching fraction Bexp[B → (ρ, ω)γ] = (1.8-0.5+0.6 ± 0.1) x 10-6 for the CKM phenomenology. Combined with the averaged branching fraction Bexp(B → K*γ) = (4.06 ± 0.26) x 10-5 measured earlier, this yields Rexp[(ρ, ω)γ/K*γ] = (4.2 ± 1.3)% for the ratio of the two branching fractions. Updating earlier theoretical analysis of these decays based on the QCD factorization framework, and constraining the CKM-Wolfenstein parameters from the unitarity fits, our results yield Bth[B → (ρ, ω)γ] = (1.38 ± 0.42) x 10-6 and Rth[(ρ, ω)γ/K*γ] = (3.3 ± 1.0)%, in agreement with the BELLE data. Leaving instead the CKM-Wolfenstein parameters free, our analysis gives (at 68% C.L.) 0.16 ≤ vertical stroke Vtd/Vts vertical stroke ≤ 0.29, which is in agreement with but less precise than the indirect CKM-unitarity fit of the same, 0.18 ≤ vertical stroke Vtd/Vts vertical stroke ≤ 0.22. The isospin-violating ratio in the B → ργ decays and the SU(3)-violating ratio in the Bd0 → (ρ0, ω)γ decays are presented together with estimates of the direct and mixing-induced CP-asymmetries in the B → (ρ, ω)γ decays within the SM. Their measurements will overconstrain the angle α of the CKM-unitarity triangle. (orig.)