LEPTONIC DECAYS OF VECTOR MESONS

2005 ◽  
Vol 14 (06) ◽  
pp. 909-921 ◽  
Author(s):  
SHASHANK BHATNAGAR

In this paper, the general structure of leptonic decay constants of vector mesons is evaluated in the framework of the Bethe–Salpeter equation under the Covariant Instantaneous Ansatz (CIA), which is a Lorentz-invariant generalization of Instantaneous Approximation (IA). The numerical values of fV in this CIA framework are on the low side in comparison to recent calculations of these quantities. However, the overall asymptotic behavior of fV is in conformity with QCD predictions.

1993 ◽  
Vol 08 (29) ◽  
pp. 2775-2783 ◽  
Author(s):  
L. MAHARANA ◽  
A. NATH ◽  
A. R. PANDA

Weak leptonic decays of light and heavy pseudoscalar mesons are studied in a field-theoretic quark model where the mesons are described by constituent quarks and antiquarks with a particular ansatz and a Harmonic oscillator wave function. With constituent quark masses and Harmonic oscillator radii for mesons as parameters of the model, decay constants are calculated and found as (fπ, fk, fD, fB) = (132 MeV , 161 MeV , 160 MeV , 115 MeV ) indicating a reasonable agreement with the experimental data wherever available. Partial decay widths and branching ratios for kinematically allowed leptonic decay processes are also estimated and compared with the experiments wherever available.


2014 ◽  
Vol 92 (5) ◽  
Author(s):  
S.N. Jena ◽  
R.N. Mishra ◽  
P.K. Nanda ◽  
S. Sahoo

Leptonic decay widths and the corresponding decay constants of neutral vector mesons are calculated in the framework of a square-root potential model of independent quarks. Starting with the assumption that a strong correlation exists between the momenta of the quark and anti-quark inside the meson so as to have their total momenta identically zero in the center-of-mass frame of the meson, we find the quark and anti-quark momentum distribution amplitude which is used to determine the transition probability amplitude for the leptonic decay of mesons. The calculated results for leptonic decay widths and the electromagnetic decay constants for the vector mesons \rho, \omega, \phi and \psi are in good agrement with the corresponding experimental values. The results for the heavy meson \Upsilon are somewhat lower than the experimental values.


2014 ◽  
Vol 29 (13) ◽  
pp. 1450067 ◽  
Author(s):  
S. N. Jena ◽  
P. K. Nanda ◽  
S. Sahoo ◽  
P. Panda

A relativistic power-law potential model of independent quarks is used to study the leptonic decays of neutral vector mesons. Here, the transition probability amplitude for leptonic decay of meson is determined from the momentum distribution function which is found from the assumption of a strong correlation existing between the momenta of quark and antiquark inside the meson. The model parameters are first determined from the application of the model to study the ground state spectra of ρ, ω, ϕ, ψ and ϒ mesons together with the radiative decay widths of mesons. The same model with no adjustable parameters is then used to evaluate the leptonic decay widths and the electromagnetic decay constants for the vector mesons ρ, ω, ϕ, ψ and ϒ. The calculated results are in remarkable agreement with the corresponding experimental values.


1993 ◽  
Vol 08 (30) ◽  
pp. 2851-2858 ◽  
Author(s):  
A. R. PANDA ◽  
K. C. ROY

We consider here the leptonic decay of vector mesons ρ, ω, ϕ, ψ and ϒ through one photon mechanism in the lowest order, and calculate their decay widths as well as the decay constants based on a field-theoretic quark model where the constituent quark field operators are described with an ansatz to satisfy equal time algebra and the translationally invariant hadron states are described with harmonic oscillator wave functions. With the harmonic oscillator radii for vector mesons and the constituent quark masses as used earlier in other investigations, the present calculations show a reasonable agreement with the experimental data in light as well as heavy flavor sectors, where available.


2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Alexander Lenz ◽  
Maria Laura Piscopo ◽  
Aleksey V. Rusov

Abstract We compute the Darwin operator contribution ($$ 1/{m}_b^3 $$ 1 / m b 3 correction) to the width of the inclusive non-leptonic decay of a B meson (B+, Bd or Bs), stemming from the quark flavour-changing transition b → $$ {q}_1{\overline{q}}_2{q}_3 $$ q 1 q ¯ 2 q 3 , where q1, q2 = u, c and q3 = d, s. The key ideas of the computation are the local expansion of the quark propagator in the external gluon field including terms with a covariant derivative of the gluon field strength tensor and the standard technique of the Heavy Quark Expansion (HQE). We confirm the previously known expressions of the $$ 1/{m}_b^3 $$ 1 / m b 3 contributions to the semi-leptonic decay b → $$ {q}_1\mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ q 1 ℓ ν ¯ ℓ , with ℓ = e, μ, τ and of the $$ 1/{m}_b^2 $$ 1 / m b 2 contributions to the non-leptonic modes. We find that this new term can give a sizeable correction of about −4 % to the non-leptonic decay width of a B meson. For Bd and Bs mesons this turns out to be the dominant correction to the free b-quark decay, while for the B+ meson the Darwin term gives the second most important correction — roughly 1/2 to 1/3 of the phase space enhanced Pauli interference contribution. Due to the tiny experimental uncertainties in lifetime measurements the incorporation of the Darwin term contribution is crucial for precision tests of the Standard Model.


2005 ◽  
Vol 140 ◽  
pp. 443-445 ◽  
Author(s):  
J.N. Simone ◽  
C. Aubin ◽  
C. Bernard ◽  
C. DeTar ◽  
M. di Pierro ◽  
...  

2018 ◽  
Vol 98 (7) ◽  
Author(s):  
A. Bazavov ◽  
C. Bernard ◽  
N. Brown ◽  
C. DeTar ◽  
A. X. El-Khadra ◽  
...  

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