Sum rule approach to the isospin symmetry breaking in 4He

The energy weighted sum rule sigma →1 is calculated on the basis of a recently proposed phenomenological model. It is found that, for a proper choice of the residual interaction parameters, the experimental value of sigma →1 can be reproduced. Inserting the calculated value of sigma →1 into a model-independent energy-weighted sum rule, the expected value of the average proton distribution radius is obtained. The agreement among the experimental, model-dependent and model-independent sum rules supports the validity of the model considered