Experimental test of the proton-neutron exchange interaction

Abstract

It has already been pointed out1 that, when a proton or neutron of relativistic velocities traverses matter, it travels until it makes a head-on collision with a neutron or proton respectively in the material, transferring nearly its whole energy to this particle, which then travels forward in very nearly the same direction. This process is repeated again, the latter particle transferring nearly its whole energy to a proton if it be a neutron, and vice versa. Let q denote the effective cross-section for either of these processes. We thus get a chain, the proton giving place to a neutron, which then gives place to a proton and so on. This effect is characteristic of an exchange interaction between a proton and a neutron, and would not occur with a non-exchange interaction. As it is important to know the form the proton-neutron interaction takes in the relativistic case, we wish to point out in this note that there is an experiment which could show if the effect mentioned above does or does not exist.