共查询到20条相似文献,搜索用时 15 毫秒
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G. Amorós S. Noguera J. Portolés 《The European Physical Journal C - Particles and Fields》2003,27(2):243-254
Within the framework of phenomenological Lagrangians we construct the effective action of QCD relevant for the study of semileptonic
decays of charmed mesons. Hence we evaluate the form factors of at leading order in the 1/N
C
expansion and, by demanding their QCD-ruled asymptotic behavior, we constrain the couplings of the Lagrangian. The features
of the model-independent parameterization of form factors are provided, and their relevance for the analysis of experimental
data are pointed out.
Received: 28 October 2002 / Published online: 24 January 2003 相似文献
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Ken-ichi Shizuya 《Physics letters. [Part B]》1981,100(1):79-83
Soft-gluon effects in nonleptonic decays of D and F mesons are studied nonperturbatively by use of a QCD multipole expansion. For reasonable values of D-meson bound-state parameters, the soft-gluon effects lead to a significant difference in the lifetimes of the D0 and D+ mesons. 相似文献
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Aubin C Bernard C Detar C Dipierro M El-Khadra A Gottlieb S Gregory EB Heller UM Hetrick J Kronfeld AS Mackenzie PB Menscher D Nobes M Okamoto M Oktay MB Osborn J Simone J Sugar R Toussaint D Trottier HD;Fermilab Lattice;MILC;HPQCD 《Physical review letters》2005,94(1):011601
We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties. 相似文献
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We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays of aB meson into excited daughter mesons. For an excited daughter meson with charm, a single form factor is needed at leading order, while five form factors and two dimensionful constants are needed to order 1/m
c
in the heavy quark expansion. For non-charmed final states, a total of four form factors are needed at leading order. For the processBD
*
X, four form factors are also needed at leading order. 相似文献
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Bortoletto D Goldberg M Horwitz N Jain V Mestayer MD Moneti GC Sharma V Shipsey IP Skwarnicki T Thulasidas M Csorna SE Letson T Alexander J Artuso M Bebek C Berkelman K Cassel DG Cheu E Coffman DM Crawford G DeWire JW Drell PS Ehrlich R Galik RS Gittelman B Gray SW Halling AM Hartill DL Heltsley BK Kandaswamy J Katayama N Kreinick DL Lewis JD Mistry NB Mueller J Namjoshi R Nandi S Nordberg E O'Grady C Peterson D Pisharody M Riley D Sapper M Silverman A Stone S Worden H Worris M Sadoff AJ 《Physical review letters》1990,64(18):2117-2120
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Ken-ichi Shizuya 《Physics letters. [Part B]》1981,105(5):406-410
The QCD multipole expansion is applied to the study of nonperturbative soft-gluon effects in semileptonic decays of charmed F mesons. For reasonable values of F-meson bound-state parameters, the soft-gluon effects activate quark-annihilation processes, leading to a significant enhancement of semileptonic decay rates. 相似文献
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Jan Finjord 《Physics letters. [Part B]》1982,109(3):227-230
We unify the color-octet weak transitions first studied in cq? annihilation models with the coherence structure of c-quark decay models. We find then, with a dominant c-quark decay contribution, and τ(D+)≈7.5×10?13 s, not inconsistent with the trends in the experimental results. 相似文献