Abdul Ebrahim

Electromagnetic Neutron Proton Mass Difference in the Skyrme Model

Abstract An allegedly complete calculation of the neutron-proton mass difference in the Skyrme model reported recently, claiming a correct sign and a 16% agreement with experiment, is re-examined. After analytical and numerical inaccuracies in the reportes calculation are eliminated, it gives a value for the mass difference which, both in magnitude and sign, is different from that reported, and is consistent with the expectation that the calculation merely represents the electromagnetic contribution to, and not a complete calculation of, the neutron-proton mass difference in the Skyrme model.

SU2 × SU2 breaking, cabibbo angle, and η → 3π decay in a nonlinear Lagrangian model

Abstract SU 2 × SU 2 breaking, Cabibbo angle, non-electromagnetic isospin breaking, and η → 3 π decay are related in a nonlinear Lagrangian model of broken chiral SU 3 × SU 3 symmetry. Excellent agreement with experiment is obtained for both the value of the Cabibbo angle and η → 3 π decay rate.

Approximate analytic chiral SU2×SU2 skyrmion solution

Abstract An approximate analytic chiral SU 2 ×SU 2 skyrmion solution that incorporates all the boundary conditions as well as the asymptotic behaviour of the exact solution is suggested. The form of the analytic solution as well as various integrals calculated from it are in excellent agreement with those obtained from the numerical solution.

Quark masses and flavor-mixing angles in a six-quark model of quantum flavordynamics

Abstract The Cabibbo-like flavor-mixing angles are related to quark masses through spontaneous symmetry breaking in an illustrative model of quantum flavordynamics based on the SU 2L x SU 2R x U 1 flavor gauge group and on six quark flavors. Theoretical and experimental consequences of the scheme are discussed.

Hierarchy of Masses for Pseudoscalar and Vector Mesons

Abstract Assuming that quark flavors beyond isospin, strangeness, and charm exist, we use the relationship between the structure of chiral symmetry breaking of the strong interaction and the Cabibbo angle in order to estimate the masses of the pseudoscalar and vector mesons carrying the fifth (beauty), sixth (truth), and seventh (illusion) quark flavors.

Structure and experimental consequences of chiral SU3 × SU3 breaking

Abstract Chiral SU 2 × SU 2 breaking, Cabibbo angle, non-electromagnetic isospin breaking, η → 3 π decay rate, and pion and kaon mass differences are related to one another in a nonlinear Lagrangian model of broken chiral SU 3 × SU 3 symmetry. The agreement with experiment is very good.

Chiral SU4 × SU4 symmetry breaking and the Cabibbo angle☆

Abstract The structure of chiral SU 4 × SU 4 symmetry breaking, in the limit of exact chiral SU 2 × SU 2 symmetry, is related to the Cabibbo angle, thus leading to a satisfactory determination of the Cabibbo angle in terms of the kaon and D-meson masses and decay constants.

General nonlinear realization of chiral SU2×SU2 symmetry in curved isospin space

The geometric method for constructing the nonlinear chiral SU2×SU2 invariant Yang–Mills Lagrangian in curved isospin space given by Meetz for a particular choice of coordinates is generalized to an arbitrary system of coordinates in curved isospin space. The resulting Lagrangian coincides with the general nonlinear chiral SU2×SU2 invariant Yang–Mills Lagrangian constructed previously using the matrix method.

Mass of the up quark

Abstract It is shown that the theoretical uncertainty connected with the PCAC formulas that relate quark masses to the pseudo-scalar meson masses, decay constants, wave function renormalization constants, and electromagnetic self-energy corrections permits the choice of a massless up quark without contradicting experiment at present. This choice, however, entails a sizable correction to Dashens formula for the electromagnetic mass difference of pions and kaons.

Some experimental consequences of Su3 noninvariance of the vacuum

Abstract A nonlinear Lagrangian model of broken chiral SU3 × SU3 symmetry is used to study the effect of SU3 noninvariance variance of the vacuum (i.e. f π ‡f K ‡f η ) on several of the predictions of chiral SU3 × SU3 symmetry breaking. It is found that the effect consistently alters the predictions towards better agreement with experiment.