Nuclear Physics Seminars

The Nab experiment is a precision study of unpolarized neutron decay. Cold neutrons decay in flight inside a custom spectrometer. The goal of Nab is to measure a, the electron-neutrino coefficient, and b, the Fierz interference term that vanishes in the standard model (SM). A measured value of a at the Nab goal precision of △a/a ≈ 10-3 will provide an independent competitive evaluation of the Vud element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. The Nab precision goal for the measurement of b is Δb ≈ 0.003. In this way, Nab will provide a critical test CKM unitarity, and, combining a and b, sensitive new tests of physics beyond the SM.