II. Quasi-elastic neutrino interactions

Abstract

A series of runs have been recently completed at the Argonne 12.5 GeV proton-synchrotron, the Z. G. S., which were designed to study the elastic scattering of neutrinos via the reaction v + n → μ - + p + . The data provided are expected to give a measure of the momentum transfer dependence or form factor for the axial vector part of the weak interaction as expressed in terms of an axial vector mass or a mean square radius for the axial vector interaction. It was envisaged in the early planning of this experiment that the high intensity of the Argonne Z. G. S. combined with the energy of neutrinos expected to be obtained from 12-5 GeV protons, would combine to make a study of elastic neutrino interactions a desirable and an advantageous type of experiment. In order to obtain a high mass target with neutrino interaction rates of several hundred per day and the possibility of muon sign determination, we used iron as the principal mass. The neutrinos thus interact ‘quasi-elastically’ with neutrons in the iron nucleus providing sufficient momentum transfer is involved so that nuclear physics effects are avoided.