Hadronic Weak Interaction Studies at the SNS

University of Tennessee, Knoxville, TN 37996

^a e-mail: nfomin@utk.edu

Published online: 25 March 2016

Abstract

Neutrons have been a useful probe in many fields of science, as well as an important physical system for study in themselves. Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics. Among them is a detailed study of the weak interaction. An overview of studies of the hadronic weak (quark-quark) as well as semi-leptonic (quark-lepton) interactions at the Spallation Neutron Source (SNS) is presented. These measurements, done in few-nucleon systems, are finally letting us gain knowledge of the hadronic weak interaction without the contributions from nuclear effects. Forthcoming results from the NPDGamma experiment will, due to the simplicity of the neutron, provide an unambiguous measurement of the long range pion-nucleon weak coupling (often referred to as h_π), which will finally test the theoretical predictions. Results from NPDGamma and future results from the n +³ He experiment will need to be complemented by additional measurements to completely describe the hadronic weak interaction.