QCD sum-rule calculation of the kinetic energy and chromo-interaction of heavy quarks inside mesons

We present a QCD sum-rule determination of the heavy-quark energy inside a heavy meson, −λ1/2mQ, which is consistent with the field-theory analog of the virial theorem. We obtaine −λ1 ≈ (0.10 ± 0.05)GeV2, significantly smaller than a previous sum-rule result, but in good agreement with recent determinations from the analysis of inclusive decays. We also present a new determination of the chromo-magnetic interaction, yielding λ2(mb) = (0.15 ± 0.03) GeV2. This implies m2B∗ − m2B = (0.60 ± 012) GeV2, in good agreement with experiment. As a by-product of our analysis, we derive the QCD sum rules for the three form factors describing the meson matrix element of a velocity-changing current operator containing the gluon field-strength tensor.