We compute the short distance coefficients for the NRQCD factorization formulas of the meson-to-vacuum matrix elements for the axial vector and vector parts of the charged weak current in the S-wave spin-singlet and-triplet b̄c mesons, respectively. The computation is carried out to order αs including relativistic corrections of all orders in q 2n, where q is the relative momentum of the b̄ and c in the meson rest frame. The relativistic corrections at order αs are new. The results reveal that the relativistic corrections to the leptonic decay rate of the Bc meson at order αs or less converge rapidly which shows a strong contrast to the uncomfortably large corrections of order α2s|q|0. The short distance coefficients listed in this paper can be employed to compute the resummation of relativistic corrections to the phenomenological measurables that involve B c and B*c production and decay.
- Heavy quark physics
ASJC Scopus subject areas
- Nuclear and High Energy Physics