Charge dependent effects on nuclear forces.

Abstract

The study of charge independence and charge symmetry on the 1 sO N-N scattering lengths provides a test of charge dependent effects of nuclear forces. All possible known contributions to the scattering lengths are considered to account for the experimental discrepancies. This problem was broken into two parts, the first considering the direct electromagnetic and the second the indirect electromagnetic effects. The effect on the charge symmetry breaking correction due to the isospin breaking part of the QCD Hamiltonian, determined by the up-down current quark mass difference, on the difference of scattering lengths for charge symmetry is determined. This is done by first calculating the effect of the QCD on the pion-nucleon coupling constants via isospin mixing, giving rise to CSB one pion exchange (OPEP) and two pion exchange (TPEP) potentials. The importance of CSB-TPEP is emphasized. The eta-nucleon coupling constant appears to be constrained by experimental values of CS to be very small.