Perturbative QCD study of {ital B}{r_arrow}{ital D}{sup ({asterisk})} decays
- Department of Physics, National Cheng-Kung University, Tainan, Taiwan, Republic of (China)
- Department of Physics, National Chung-Cheng University, Chia-Yi, Taiwan, Republic of (China)
We compute various form factors involved in {ital B}{r_arrow}{ital D}{sup ({asterisk})} transitions based on the perturbative QCD formalism, which includes Sudakov effects from the resummation of large radiative corrections in a heavy-light system. A two-parameter model wave function for {ital D}{sup ({asterisk})} mesons is fixed using data of the nonleptonic decays {ital B}{r_arrow}{ital D}{sup ({asterisk})}{pi}, from which the ratio of the decay constants {ital f}{sub {ital D}{asterisk}}/{ital f}{sub {ital D}}=0.92 is obtained. We then derive the spectrum of the semileptonic decay {ital B}{r_arrow}{ital D}{asterisk}{ital l}{nu} in the fast recoil region of the {ital D}{asterisk} meson, and extract the CKM matrix element {parallel}{ital V}{sub {ital cb}}{parallel}=0.043{times}(0.12 GeV/{ital f}{sub {ital B}}){times}(0.14 GeV/{ital f}{sub {ital D}}), {ital f}{sub {ital B}} and {ital f}{sub {ital D}} being the {ital B} and {ital D} meson decay constants, respectively. Here we adopt the convention with the pion decay constant {ital f}{sub {pi}}=93 MeV. With these outcomes, we evaluate the decay rate of {ital B}{r_arrow}{ital DD}{sub {ital s}}, and estimate the ratio {ital f}{sub {ital D}{sub {ital s}}}/{ital f}{sub {ital D}}=0.98 from data. Contributions of internal {ital W}-emission and {ital W}-exchange diagrams are briefly discussed. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 284061
- Journal Information:
- Physical Review, D, Vol. 53, Issue 9; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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