Resummation of running coupling effects in semileptonic {ital B} meson decays and extraction of {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar}

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.52.3929· OSTI ID:249529

Ball, P ^[1]; Beneke, M ^[2]; Braun, V M ^[3]

---

1. CERN, Theory Division, CH-1211 Geneve 23 (Switzerland)
2. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
3. DESY, Notkestrasse 85, D-22603 Hamburg (Germany)

We present a determination of {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar} from semileptonic {ital B} decays that includes resummation of supposedly large perturbative corrections, originating from the running of the strong coupling. We argue that the low value of the BLM scale found previously for inclusive decays is a manifestation of the renormalon divergence of the perturbative series starting already in third order. A reliable determination of {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar} from inclusive decays is possible if one either uses a short-distance {ital b} quark mass or eliminates all unphysical mass parameters in terms of measured observables, such that all infrared contributions of order 1/{ital m}{sub {ital b}} cancel explicitly. We find that using the M{bar S} running mass significantly reduces the perturbative coefficients already in low orders. For a semileptonic branching ratio of 10.9% we obtain {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar}({tau}{sub {ital B}}/1.50 ps){sup 1/2}=0.041{plus_minus}0.002 from inclusive decays, in good agreement with the value extracted from exclusive decays.

• OSTI ID: 249529
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 7 Vol. 52; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
B MESONS
BRANCHING RATIO
COUPLING
KOBAYASHI-MASKAWA MATRIX
MASS
PERTURBATION THEORY
QUARKS
SEMILEPTONIC DECAY