The effect of short range correlation on the inelastic C2 and C4 form factors of 18O nucleus

The effect of short range correlations on the inelastic Coulomb form factors for excited +2 states (1.982, 3.919, 5.250 and 8.210MeV) and +4 states (3.553, 7.114, 8.960 and 10.310 MeV) in O18 is analyzed. This effect (which depends on the correlation parameterβ) is inserted into the ground state charge density distribution through the Jastrow type correlation function. The single particle harmonic oscillator wave function is used with an oscillator size parameter .b The parameters β and b are adjusted for each excited state separately so as to reproduce the experimental root mean square charge radius of .18O The nucleusO18 is considered as an inert core of C12 with two protons and four neutrons distributed over 212521211sdp−− active orbits. The total transition charge density comes from both the model space and core polarization transition charge densities. The realistic effective interaction of Reehal–Wildenthal (REWIL) is used for this model space. It is found that the introduction of the effect of short range correlations is necessary for obtaining a remarkable improvement for the calculated inelastic Coulomb form factors and considered as an essential for explanation the data amazingly throughout the whole range of considered momentum transfer.

Mass Spectra and Decay Constants of Heavy-Light Mesons: A Case Study of QCD Sum Rules and Quark Model

We visited mass spectra and decay constants of pseudoscalar and vector heavy-light mesons (B, Bs, D, and DS) in the framework of QCD sum rule and quark model. The harmonic oscillator wave function was used in quark model while a simple interpolating current was used in QCD sum rule calculation. We obtained good results in accordance with the available experimental data and theoretical studies.

CHARMONIUM SPECTRA AND DECAYS IN A SEMIRELATIVISTIC MODEL

We investigate the spectra and decays of charmonium [Formula: see text] system in a semirelativistic potential model. The Hamiltonian of our model consists of a relativistic kinetic energy term, a vector Coulomb-like potential and a scalar confining potential. From this Hamiltonian a spinless wave equation is obtained. The wave equation is then reduced to the form of a single particle Schrödinger equation. The spin dependent potentials are introduced as a perturbation. The three-dimensional harmonic oscillator wave function is employed as a trial wave function and the [Formula: see text] mass spectra is obtained by the variational method. The model parameters and the wave function that reproduce the mass spectra of the [Formula: see text] mesons are then used to investigate some of the decay properties. The results obtained are then compared with the experimental data and with the predictions of other theoretical models. We also propose possible [Formula: see text] assignments for the recently observed charmonium or charmonium-like states.

Analytical Evaluation of Two-Center Franck-Condon Overlap Integrals over Harmonic Oscillator Wave Function

A unified treatment of Franck-Condon (FC) overlap integrals with arbitrary values of parameters is described. These integrals are represented in terms of binomial coefficients. For quick calculations, the binomial coefficients are stored in the memory of the computer. Therefore, the CPU time has been greatly reduced. Numerical results presented agree excellently with those obtained in the literature

COLOR-STRAIGHT FOUR-QUARK OPERATORS AND LIFETIMES OF b-FLAVORED HADRONS

Using the relation between the harmonic oscillator wave function and the light quark scattering form factor, the expectation values of color-straight four-quark operators are evaluated and found to be directly proportional to the cubic power of the oscillator strength. It is predicted that the ratio τ(Λb)/τ(B)≈0.79(0.84) due to the factorizable (nonfactorizable) piece, against the experimental 0.79±0.06. Notwithstanding the numerical prediction, the present study shows that the four-quark operators play a role as far the lifetimes of b-flavored hadrons are concerned.

EXCLUSIVE SEMILEPTONIC DECAYS OF D AND B-MESONS IN A RELATIVISTIC QUARK MODEL

The exclusive semileptonic decays like D0 and B0 mesons are studied in the framework of a relativistic field-theoretic quark model, where translationally invariant hadronic states are described by constituent quark field operators satisfying equal time algebra and a harmonic oscillator wave function. The present estimations to the relevant form factors and their q2 dependence, without any free parameters, show a reasonable agreement with the available experimental measurements and Heavy Quark Effective Theory (HQET) and other model calculations. Further, the calculated decay widths and their ratios, and the polarization ratios for decay processes also have a reasonable agreement with the available experiments and other model estimations.

WEAK RADIATIVE DECAYS OF PSEUDOSCALAR CHARMED MESONS

We consider here radiative weak decays of charmed mesons such as [Formula: see text] and [Formula: see text] in a quark model where in general a translationally invariant SU(6) hadronic state is described by constituent quark field operators satisfying equal time algebra and a harmonic oscillator wave function. The model had its earlier success during its application to a variety of hadronic phenomena, and here also, without any free parameters, it calculates the branching ratios as [Formula: see text] and [Formula: see text]. Such calculations are very close to the estimations of Asthana and Kamal, and thus is consistent with the QCD enhancement of the latter branching ratio with respect to the former.

WEAK LEPTONIC DECAY OF LIGHT AND HEAVY PSEUDOSCALAR MESONS IN A FIELD-THEORETIC QUARK MODEL

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.