N. Barik

PION-CLOUD EFFECTS ON THE ELECTROMAGNETIC PROPERTIES OF NUCLEONS IN A QUARK MODEL

Incorporating corrections for the center-of-mass motion and pion-cloud effects the nucleon electromagnetic form factors are computed in an independent quark model based on the Dirac equation with a confining potential The static quantities like magnetic moment μN, charge radius and axial vector coupling constant (gA)n→peν of the nucleons computed in this model are in reasonable agreement with the experiment. The pseudoscalar and the pseudovector pion-nucleon coupling constants are obtained as gNNπ=13.52 and fNNπ=0.284, which are in excellent agreement with the experimental data.

MAGNETIC MOMENTS OF OCTET BARYONS IN A RELATIVISTIC POTENTIAL MODEL WITH PIONIC AND CENTER OF MASS CORRECTIONS

The magnetic moments of the octet baryons are calculated in a chiral symmetric inde-pendent quark potential model of the form The residual interaction arising from the quark-pion coupling over and above the dominant confining one represented by this phenomenological potential, is treated as a low order perturbation. The correction due to center of mass motion is also taken into account appropriately. The results are in reasonable agreement with the experimental data.

RADIATIVE LEPTONIC DECAY OF Ds AND D MESONS

The radiative leptonic decays Ds → μνμγ and D → μνμγ are investigated at the tree level within the relativistic independent quark model based on the confining potential in the scalar–vector harmonic form. The branching ratios for these decays in the vanishing lepton mass limit are obtained as ℬr(Ds → μνμγ) = 4.94×10-4 and ℬr(D → μνμγ) = 3.34×10-5, which includes the contributions of the internal bremsstrahlung and structure dependent diagrams at the level of the quark constituents. Finally, the photon energy spectra as predicted here is found to be symmetric about the peak value of the photon energy at

Magnetic Dipole Transitions of

E_\gamma = \frac{M_{D_{(s)}}}{4}

B_c

.

and

We study M1-transitions involving mesons:

B_c^*

B_c(1s)

mesons in the Relativistic Independent Quark Model

,

Semileptonic decays of the B{sub c} meson

B_c^*(1s)

Electromagnetic polarisabilities of the proton in an independent particle potential model

,