B -> D* at zero recoil revisited

Understand

We examine the B -> D* form factor at zero recoil using a continuum QCD approach rooted in the heavy quark sum rules framework.

• A refined evaluation of the radiative corrections as well as the most recent estimates of higher order power terms together with more careful continuum calculation are included.
• An upper bound on the form factor of F(1)< 0.93 is derived, based on just the positivity of inelastic contributions.
• A model-independent estimate of the inelastic contributions shows they are quite significant, lowering the form factor by about 6% or more.