Andrey Grozin

Asymptotics of heavy-meson form factors

Using methods developed for hard exclusive QCD processes, we calculate the asymptotic behavior of heavy-meson form factors at large recoil. It is determined by the leading- and subleading-twist meson wave functions. For 1{lt}{vert_bar}v{center_dot}v{sup {prime}}{vert_bar}{lt}m{sub Q}/{Lambda}, the form factors are dominated by the Isgur-Wise function, which is determined by the interference between the wave functions of leading and subleading twist. At {vert_bar}v{center_dot}v{sup {prime}}{vert_bar}{gt}m{sub Q}/{Lambda}, they are dominated by two functions arising at order 1/m{sub Q} in the heavy-quark expansion, which are determined by the leading-twist wave function alone. The sum of these contributions describes the form factors in the whole region {vert_bar}v{center_dot}v{sup {prime}}{vert_bar}{gt}1. As a consequence, there is an exact zero in the form factor for the scattering of longitudinally polarized B{sup {asterisk}} mesons at some value v{center_dot}v{sup {prime}}{approximately}m{sub b}/{Lambda}, and an approximate zero in the form factor of B mesons in the timelike region (v{center_dot}v{sup {prime}}{approximately}{minus}m{sub b}/{Lambda}). We obtain the evolution equations and sum rules for the wave functions of leading and subleading twist as well as for their moments. We briefly discuss applications to heavy-meson pair production in e{sup +}e{sup {minus}} collisions. {copyright} {ital 1997} {ital The American Physical Society}

Three Loop Cusp Anomalous Dimension in QCD

We present the full analytic result for the three loop angle-dependent cusp anomalous dimension in QCD. With this result, infrared divergences of planar scattering processes with massive particles can be predicted to that order. Moreover, we define a closely related quantity in terms of an effective coupling defined by the lightlike cusp anomalous dimension. We find evidence that this quantity is universal for any gauge theory and use this observation to predict the nonplanar n(f)-dependent terms of the four loop cusp anomalous dimension.

Light quark mass effects in the on-shell renormalization constants

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.

Simultaneous decoupling of bottom and charm quarks

We compute the decoupling relations for the strong coupling, the light quark masses, the gauge-fixing parameter, and the light fields in QCD with heavy charm and bottom quarks to three-loop accuracy taking into account the exact dependence on mc/mb. The application of a low-energy theorem allows the extraction of the three-loop effective Higgs-gluon coupling valid for extensions of the Standard Model with additional heavy quarks from the decoupling constant of αs.

Three-loop HQET vertex diagrams for B0?bar B0 mixing

Three-loop vertex diagrams in HQET needed for sum rules for B0–0 mixing are considered. They depend on two residual energies. An algorithm of reduction of these diagrams to master integrals has been constructed. All master integrals are calculated exactly in d dimensions; their e expansions are also obtained.

B0−B¯0mixing at next-to-leading order

We compute the perturbative corrections to the HQET sum rules for the matrix element of the \Delta B=2 operator that determines the mass shift of

Upper limits on electric dipole moments of τ-lepton and W-boson

B^0

Hybrid renormalization of penguins and dimension-5 heavy-light operators

,

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\bar{B}^0

Towards a next-to-next-to-leading order analysis of matching in B0−B¯0 mixing

states. Technically, we obtain analytically the non-factorizable contributions at order