arXiv subjects
Publications and source records attributed to A. Grozin.
We present the three-loop QCD corrections to the quark chromomagnetic moment including two different nonzero masses. This is a necessary ingredient to obtain the corresponding corrections to the chromomagnetic coefficient in the Heavy Quark Effective Theory (HQET) Lagrangian.
We compute the three-loop relation between the pole and the minimally subtracted quark mass allowing for virtual effects from a second massive quark. We also consider the analogue effects for the on-shell wave function renormalization constant.
We discuss how one can determine the average kinetic energy of the heavy quark inside heavy mesons from differential distributions in $B$ decays. A new, so-called third, sum rule for the $b\rightarrow c$ transition is derived in the small velocity (SV) limit. Using this sum rule and the existing data on the momentum dependence in the $B\rightarrow D^*$ transition (the slope of the Isgur-Wise function) we obtain a new lower bound on the parameter $μ_π^2 = (2M_B)^{-1}\langle B |\bar b (i\vec{D})^2 b |B\rangle $ proportional to the average kinetic energy of $b$ quark inside $B$ meson. The existing data suggest $μ_π^2 > 0.4$~GeV$^2$ and (from the ``optical'' sum rule) $\overlineΛ > 500$ MeV, albeit with some numerical uncertainties.