Nuclear Physics Seminars

The Nab collaboration at the Spallation Neutron Source (SNS) aims to measure the electron-neutrino correlation parameter "a" with a relative uncertainty of about 10^{-3}, and the Fierz interference term "b" with absolute uncertainty of 3 x 10^{-3}. Nab will use a novel "time of flight" (TOF) EM field spectrometer and segmented Si detectors. The scientific motivation is to provide an independent measurement of the ratio of axial-vector to vector coupling constants of the nucleon to an uncertainty of 0.03% and to test the unitarity of the CKM quark mixing matrix. In the Nab experiment, "a" is determined by combined precise determinations of the electron energy and the proton time of flight. In this talk, we present the motivation of the Nab experiment, the principle and the uncertainty analysis of the measurement of “a”.