Dependence of $|V_{ub}/V_{cb}|$ on Fermi momentum $p_{{}_F}$ in ACCMM model

Abstract

The Gaussian width of Fermi momentum, $p_{{}_F}$, is the most important parameter of the ACCMM model, and its value is essential in the determination of $|V_{ub}/V_{cb}|$ because the experimental analysis is allowed only at the end-point region of inclusive semileptonic $B$-decay spectrum. We extract the value of $|V_{ub}/V_{cb}|$ as a function of $p_{{}_F}$. We also calculate the parameter $p_{{}_F}$ in the relativistic quark model using the variational method, and obtain $p_{{}_F}=0.54$ GeV which is much larger than the commonly used value, $\sim 0.3$ GeV, in experimental analyses. When we use $p_{{}_F}=0.5$ GeV instead of 0.3 GeV, the value of $|V_{ub}/V_{cb}|$ from ACCMM model is increased by a factor 1.81, and can give a good agreement with Isgur {\it et al.} model.

1. Section 2 has been revised by considering the fact that in the real experimental situation the only measured quantity is the number of events in the high $E_l$ region compared to the total semi- leptonic event number. 2. The article by C. Greub and D. Wyler (Phys. Lett. B295 (1992) 293) has been included in references, which reports a similar conclusion for the value of $p_{{}_F}$ ($p_{{}_F}$=566 MeV), even though they used the different approach. 3. This article will be published in Z. Phys. C (1995)

References in corpus (2)

• QCD Predictions for Lepton Spectra in Inclusive Heavy Flavour Decays
• Hadronic Spectrum in Inclusive Semileptonic B Decays

Cited by in corpus (11)

• Decay Constants of $B$, $B^{\ast }$ and $D$, $D^{\ast }$ Mesons in Relativistic Mock Meson Model
• Average Kinetic Energy of Heavy Quark and Virial Theorem
• Decay Constants and Semileptonic Decays of Heavy Mesons in Relativistic Quark Model
• Average Kinetic Energy of Heavy Quark in Semileptonic B Decay
• Momentum Distribution in the Decay B-->J/psi+X
• The Average Kinetic Energy of the Heavy Quark in ${\Lambda }_b$ in the Bethe-Salpeter Equation Approach
• The gluonic B and J/psi decays into the eta' meson
• Motion of b-quark inside B meson: the Parton Model vs. the ACCMM Model
• Determination of HQET parameter λ_1 from Inclusive Semileptonic B Meson Decay Spectrum
• A New Model-independent Method of Determining |V_{ub}/V_{cb}|
• Ratios of vector and pseudoscalar $B$ meson decay constants in the light-cone quark model