Nuclear charge asymmetry in the a = 3 nuclei

Abstract

The nuclear charge asymmetry in the A = 3 system is determined by making a perturbative estimate of the direct electromagnetic (e.m.) contribution to the 3He- 3H binding energy difference. All local e.m. contributions are estimated in an almost model-independent way using experimental charge form factors and the relation exploited previously by Fabre de la Ripelle and Friar only for the contribution of the static Coulomb interaction. Model-dependent wave functions are used for the contribution of the small non-local terms of the e.m. interaction and the proton-neutron mass difference. Only 81 ± 29 keV of the experimental binding-energy difference has to be attributed to nuclear charge asymmetry, an amount smaller than previous estimates. The nearly model-independent method is used to estimate the contribution of some two-body charge asymmetric potentials, both theoretical and phenomenological, to the binding-energy difference.