HBT interferometry with rescattering in the medium

We derive the identical-particle correlation function when the particles are allowed to elastically rescatter in the medium in which they were produced. We then specialize to the case where the scatterers are static, localized potentials. In one dimension the correlation function is unaffected by the rescattering. In three dimensions, and with a Gaussian source, the ratio Rout/Rside increases with momentum from less than one to more than one. Specific numbers are used to illustrate kaon interferometry. (author)