Abstract :
The sum of the factorizable long- and short-distance cc̄ contributions to the B→K∗γ amplitude vanishes as a consequence of the gauge invariance. Moreover, the short- and long-distance contributions vanish, separately, if defined in a gauge-invariant way. In view of this, we dispute a popular estimate of the long-distance effects in the B→K∗γ decay in terms of the B→K∗ semileptonic form factors and the decay constants of the cc̄ resonances. We show that a nonzero value obtained within this approach is an artifact of using a gauge-dependent prescription for the resonance contribution extended to q2=0.
