Effective convection current in the shell-model
A recent investigation of the isospin forbidden electromagnetic transition of40Ca indicated that the convection current calculated in the shell-model should be modified by an “effective charge” to reproduce the transverse form factor. We propose a definition for the current operator and a prescription for the calculation of its matrix elements in the shell-model. We apply this prescription to40Ca. This definition satisfies the equation of continuity and reproduces the experimental data.