A QUARK-MODEL FIT FOR THE ELECTROMAGNETIC PROPERTIES OF OCTET BARYONS

1992 ◽  
Vol 07 (12) ◽  
pp. 2841-2861 ◽  
Author(s):  
S. N. JENA ◽  
S. PANDA
Keyword(s):  
Quark Model ◽  
Magnetic Moments ◽  
Center Of Mass ◽  
Axial Vector ◽  
Form Factors ◽  
Electromagnetic Properties ◽  
Coupling Constant ◽  
Vector Coupling ◽  
Pion Nucleon ◽  
Octet Baryons

A simple independent-quark model based on the Dirac equation with an equally mixed scalar–vector linear confining potential model is used to obtain a fit for the electromagnetic properties — like the magnetic moments, charge radii and axial-vector coupling-constant ratios — of octet baryons, taking into account the appropriate center-of-mass corrections. This fit is extended to include the quark-core contributions to the nucleon electromagnetic form factors [Formula: see text], [Formula: see text], [Formula: see text] and the axial-vector form factor GA(q2). The respective root-mean-square radii associated with [Formula: see text] and GA(q2) come out as [Formula: see text] and [Formula: see text]. The possibility of restoring in this model the chiral symmetry in the usual way is discussed and the pion-nucleon coupling constant is found as gπ NN = 13.72 as compared to (gπ NN ) exp ≃ 13.

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

1992 ◽  
Vol 07 (27) ◽  
pp. 6813-6831 ◽  
Author(s):  
N. BARIK ◽  
S.N. JENA ◽  
D.P. RATH
Keyword(s):  
Quark Model ◽  
Center Of Mass ◽  
Axial Vector ◽  
Form Factors ◽  
Coupling Constants ◽  
Electromagnetic Properties ◽  
Mass Motion ◽  
Pion Cloud ◽  
Vector Coupling ◽  
Pion Nucleon

Incorporating corrections for the center-of-mass motion and pion-cloud effects the nucleon electromagnetic form factors [Formula: see text] are computed in an independent quark model based on the Dirac equation with a confining potential [Formula: see text] The static quantities like magnetic moment μN, charge radius [Formula: see text] 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.

Contributions of the Pion-Cloud to the Magnetic Moments of Nucleon Octet in a Relativistic Quark Model

1998 ◽  
Vol 07 (04) ◽  
pp. 425-440 ◽  
Author(s):  
S. N. Jena ◽  
M. R. Behera ◽  
S. Panda
Keyword(s):  
Quark Model ◽  
Effective Potential ◽  
Magnetic Moments ◽  
Mass Motion ◽  
Relativistic Quark Model ◽  
Coupling Constant ◽  
Centre Of Mass ◽  
Pion Cloud ◽  
Pion Nucleon ◽  
Octet Baryons

The contributions of the pion-cloud to the magnetic moments of the nucleon octet is investigated in a chiral symmetric independent-quark model. The effective potential representing phenomenologically the confining interaction due to the non-perturbative multigluon mechanism is taken in the form [Formula: see text]. The pion-nucleon coupling constant [Formula: see text] comes out to be 14.43, as compared to the experimental value 14.1. The results obtained for the magnetic moments of the octet baryons, after incorporating the centre-of-mass motion and the low-order pionic corrections, agree reasonably with the experiment.

Electromagnetic Form Factors and Static Properties of the Nucleons in a Chiral Symmetric Quark Model

1998 ◽  
Vol 07 (01) ◽  
pp. 69-88 ◽  
Author(s):  
S. N. Jena ◽  
M. R. Behera
Keyword(s):  
Experimental Data ◽  
Quark Model ◽  
Center Of Mass ◽  
Axial Vector ◽  
Form Factors ◽  
Coupling Constants ◽  
Mass Motion ◽  
Static Properties ◽  
Vector Coupling ◽  
Pseudo Scalar

Nucleon charge and magnetic form factors [Formula: see text] are computed in an independent-quark model with an equally mixed scalar and vector confining potential in square root form taking into account the corrections due to center-of-mass motion and pion-clound effects. The values obtained for the nucleon static properties such as the magnetic moment, charge radius and axial vector coupling constant in the neutron beta decay process agree reasonably with the corresponding experimental data. The pseudo-scalar and pseudo-vector pion-nucleon coupling constants are found to be gNNπ=13.43 and fNNπ=0.282, which are in excellent agreement with the experimental data.

scholarly journals Self-Consistent Pushing and Cranking Corrections to the Meson Fields of the Chiral Quark-Loop Soliton

1998 ◽  
Vol 07 (01) ◽  
pp. 121-138 ◽  
Author(s):  
M. Schleif ◽  
R. Wünsch ◽  
T. Maissner
Keyword(s):  
Constituent Quark ◽  
Magnetic Moments ◽  
Axial Vector ◽  
Mass Splitting ◽  
Energy Functional ◽  
Coupling Constant ◽  
Quark Loop ◽  
Vector Coupling ◽  
Quark Masses ◽  
Axial Vector Coupling

We study translational and spin-isospin symmetry restoration for the two-flavor chiral quark-loop soliton. Instead of a static soliton at rest we consider a boosted and rotating hedgehog soliton. Corrected classical meson fields are obtained by minimizing a corrected energy functional which has been derived by semi-classical methods (variation after projection). We evaluate corrected meson fields in the region 300 MeV ≤ M≤ 600 MeV of constituent quark masses M and compare them with the uncorrected fields. We study the effect of the corrections on various expectation values of nuclear observables such as the root-mean square radius, the axial-vector coupling constant, magnetic moments and the delta-nucleon mass splitting.

MAGNETIC MOMENTS OF OCTET BARYONS IN A RELATIVISTIC QUARK MODEL WITH CHIRAL SYMMETRY

1993 ◽  
Vol 08 (25) ◽  
pp. 4563-4576 ◽  
Author(s):  
S.N. JENA ◽  
S. PANDA
Keyword(s):  
Quark Model ◽  
Chiral Symmetry ◽  
Effective Potential ◽  
Magnetic Moments ◽  
Center Of Mass ◽  
Relativistic Quark Model ◽  
First Approximation ◽  
Mass Correction ◽  
Experimental Values ◽  
Octet Baryons

Under the assumption that baryons are an assembly of independent quarks confined in a first approximation by an effective potential [Formula: see text], which presumably represents the nonperturbative gluon interactions, the magnetic moments of octet baryons have been calculated by considering perturbatively the contributions of the residual quark-pion coupling arising out of the requirement of chiral symmetry over and above the necessary center-of-mass correction. The results so obtained agree quite well with the corresponding experimental values.

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