The Decay $B\to K^*γ$ from QCD Sum Rules

Abstract

Using the QCD sum rules approach and the complete leading--logarithmic short--distance coefficients determining the penguin--amplitude, we obtain $B(B\to K^*γ) = (6.8\pm 2.4)\cdot 10^{-5}$ for top--quark masses in the range (150--200) GeV and $|V_{cb}| = 0.035$ for $τ_B = 1.5\,\text{ps}$. The ratio to the inclusive rate is $B(B\to K^*γ)/B(B\to X_sγ) = (20\pm 6)\% $.