2021 journal article

Improved Neutron Lifetime Measurement with UCN τ

PHYSICAL REVIEW LETTERS, 127(16), 162501.

By: F. Gonzalez*, E. Fries*, C. Cude-Woods n, T. Bailey n, M. Blatnik*, L. Broussard*, N. Callahan*, J. Choi n ...

co-author countries: France 🇫🇷 Russian Federation 🇷🇺 United States of America 🇺🇸
Source: Web Of Science
Added: October 26, 2021

We report an improved measurement of the free neutron lifetime τ_{n} using the UCNτ apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns in 2017 and 2018. We extract τ_{n} from three blinded, independent analyses by both pairing long and short storage time runs to find a set of replicate τ_{n} measurements and by performing a global likelihood fit to all data while self-consistently incorporating the β-decay lifetime. Both techniques achieve consistent results and find a value τ_{n}=877.75±0.28_{stat}+0.22/-0.16_{syst} s. With this sensitivity, neutron lifetime experiments now directly address the impact of recent refinements in our understanding of the standard model for neutron decay.