Study of B→Xγ decays and determination of |Vtd/Vts|

Abstract

Using a sample of 471 × 10 6 B ¯¯¯ B events collected with the BABAR detector, we study the sum of seven exclusive final states B → X s ( d ) γ , where X s ( d ) is a strange (nonstrange) hadronic system with a mass of up to 2.0 GeV / c 2 . After correcting for unobserved decay modes, we obtain a branching fraction for b → d γ of ( 9.2 ± 2.0 ( stat ) ± 2.3 ( syst ) ) × 10 − 6 in this mass range, and a branching fraction for b → s γ of ( 23.0 ± 0.8 ( stat ) ± 3.0 ( syst ) ) × 10 − 5 in the same mass range. We find B ( b → d γ ) B ( b → s γ ) = 0.040 ± 0.009 ( stat ) ± 0.010 ( syst ) , from which we determine | V t d / V t s | = 0.199 ± 0.022 ( stat ) ± 0.024 ( syst ) ± 0.002 ( th ) .