Isospin Violation and the Proton's Strange Form Factors

The strange form factors of the proton are basic to an understanding of proton structure, and are presently the focus of many experiments. Before the strangeness effects can be extracted from data, it is necessary to calculate and remove effects due to isospin violation, which exist independently of the strange quark but which contribute nevertheless to the experimentally measured ``strange’’ form factors. A discussion of the isospin violating contributions to vector form factors is given here in the context of heavy baryon chiral perturbation theory.