2-PION EXCHANGE CONTRIBUTIONS TO NUCLEAR-CHARGE ASYMMETRY

In a nonrelativistic formalism we derive a charge-symmetry-breaking (C SB) two-pion exchange interaction V-nn(2 pi)-V-pp(2 pi), which include s both CSB vertex corrections and the CSB effect of propagators arisin g from the mass differences of the intermediate baryons in different c harge states. While the former are small, the latter gives a contribut ion of the sign and scale comparable to the experimental difference in the effective range parameters and the binding energy difference betw een H-3 and He-3.