Progress on the BL2 beam measurement of the neutron lifetime

Abstract

A precise value of the neutron lifetime is important in several areas of physics, including determinations of the quark-mixing matrix element | V ud |, related tests of the Standard Model, and predictions of light element abundances in Big Bang Nucleosynthesis models. We report the progress on a new measurement of the neutron lifetime utilizing the cold neutron beam technique. Several experimental improvements in both neutron and proton counting that have been developed over the last decade are presented. This new effort should yield a final uncertainty on the lifetime of 1 s with an improved understanding of the systematic effects.