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

• Published in: Physics letters. B Vol. 595; no. 1-4; pp. 323 - 338
• Main Authors: Ali, Ahmed, Lunghi, Enrico, Parkhomenko, Alexander Ya
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 12-08-2004; Elsevier Science
• Subjects: Exact sciences and technology; Physics; Isospin; Branching ratio; Mixing; Wolfenstein parameters; Asymmetry; SU theory; Meson decay; Factorization; B mesons; Quantum chromodynamics; Unitarity
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2004.06.039

We study the implication of the recent measurement by the BELLE Collaboration of the averaged branching fraction B̄exp[B→(ρ,ω)γ]=(1.8+0.6−0.5±0.1)×10−6 for the CKM phenomenology. Combined with the averaged branching fraction B̄exp(B→K∗γ)=(4.06±0.26)×10−5 measured earlier, this yields R̄exp[(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 B̄th[B→(ρ,ω)γ]=(1.38±0.42)×10−6 and R̄th[(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⩽|Vtd/Vts|⩽0.29, which is in agreement with but less precise than the indirect CKM-unitarity fit of the same, 0.18⩽|Vtd/Vts|⩽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.