Perturbative corrections to curvature sum rules

Two new sum rules were recently discovered by Le Yaouanc et al. by applying the operator product expansion to the nonforward matrix element of a time-ordered product of b-->c currents in the heavy-quark limit of QCD. They lead to the constraints sigma(2)>5rho(2)/4 and sigma(2)>3(rho(2))(2)/5+4rho(2)/5 on the curvature of the (B) over bar -->D-(*) Isgur-Wise function, both of which imply the absolute lower bound sigma(2)>15/16 when combined with the Uraltsev bound rho(2)>3/4 on the slope. This paper calculates order alpha(s) corrections to these bounds, increasing the accuracy of the resultant constraints on the physical form factors. The latter may have implications for the determination of |V-cb| from exclusive semileptonic B meson decays.