Status of the UCNτ experiment

¹ Los Alamos National Laboratory, Los Alamos, NM 87544, USA
² Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614, USA
³ Center for Exploration of Energy and Matter and Department of Physics, Indiana University, Bloomington, IN 47408, USA
⁴ Triangle Universities Nuclear Laboratory and Physics Department, North Carolina State University, Raleigh, NC 27695, USA
⁵ Department of Physics, Tennessee Technical University, Cookeville, TN 38505, USA
⁶ Kellog Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
⁷ Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
⁸ Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
⁹ Institut Laue-Langevin, Grenoble, France
¹⁰ Department of Physics and Astronomy, DePauw University, Greencastle, IN 46135, USA
¹¹ Center for Experimental Nuclear Physics and Astrophysics, University of Washington, Seattle, WA 98195, USA
¹² Joint Institute for Nuclear Research, Dubna, Moscow region 141980, Russia
¹³ Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA

^a e-mail: pattie@etsu.edu

Published online: 12 December 2019

Abstract

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, τ_n = 877.7s (0.7s)_stat (+0.4/−0.2s)_sys. We discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.25 s measurement of the neutron lifetime with UCNτ.