2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42903Two 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 $b \to c$ currents in the heavy-quark limit of QCD. They lead to the constraints $σ^2 > 5ρ^2/4$ and $σ^2 > 3(ρ^2)^2/5 + 4ρ^2/5$ on the curvature of the $\bar{B} \to D^{(*)}$ Isgur-Wise function, both of which imply the absolute lower bound $σ^2 > 15/16$ when combined with the Uraltsev bound $ρ^2 > 3/4$ on the slope. This paper calculates order $α_s$ 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.19 pages, 4 figures; minor clarifications, additional figureHigh Energy Physics - Phenomenologytext