Comment on nonperturbative effects in B → Xsγ

Uncertainties in the theoretical prediction for the inclusive B → Xsγ decay rate are discussed. We emphasize that there is no operator product expansion for this process. Nonetheless, some nonperturbative effects involving a virtual cc loop are calculable using the operator product expansion. They give a contribution to the decay rate that involves the B meson matrix element of an infinite tower of operators. The higher dimension operators give effects that are only suppressed by powers of mbΛQCDmc2 ∼ 0.6, but come with small coefficients.