2 research outputs found
Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the Diquark-model
The diquark model is used to calculate the electromagnetic polarizabilities
and charge radii of the nucleons for three different potentials. Making the
scalar diquark lower in mass introduces a mixing angle between the
and states ,which allows an
improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix
and the magnetic moment operator to the diquark model gives constraints on this
mixing. We obtain for the Richardson potential
Additional pion cloud contributions could
improve on all six results.Comment: 15 Pages, Latex, Figs on request, to be published Phys.Lett.B. Minor
errors corrected and eqn 5,6,8,9 correcte
Electromagnetic Polarisability of the Nucleon in Chiral Perturbation Theory
We compute the polarisability of the nucleon to leading order in chiral
perturbation theory. The contributions from kaons and baryon resonances as
intermediate states are included in addition to the contribution from pions and
nucleons that had been previously computed. The isoscalar operators are
dominated by the infrared behaviour of pion loops giving rise to a
coefficient. In contrast, the isovector operators are dominated by loops
involving kaons, giving a coefficient, and further demonstrates that
the strange quark is an important component of the nucleon. In addition, the
inclusion of the decuplet of baryon resonances as intermediate states
substantially modifies the result found from the octet baryons alone for the
isoscalar polarisability.Comment: 11 pages (uses harvmac, figures available upon request) , UCSD/PTH
92-30, QUSTH-92-0