Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection

R W Pattie Jr; N B Callahan; C Cude-Woods; E R Adamek; L J Broussard; S M Clayton; S A Currie; E B Dees; X Ding; E M Engel; D E Fellers; W Fox; P Geltenbort; K P Hickerson; M A Hoffbauer; A T Holley; A Komives; C-Y Liu; S W T MacDonald; M Makela; C L Morris; J D Ortiz; J Ramsey; D J Salvat; A Saunders; S J Seestrom; E I Sharapov; S K Sjue; Z Tang; J Vanderwerp; B Vogelaar; P L Walstrom; Z Wang; W Wei; H L Weaver; J W Wexler; T L Womack; A R Young; B A Zeck

doi:10.1126/science.aan8895

Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection

Science. 2018 May 11;360(6389):627-632. doi: 10.1126/science.aan8895. Epub 2018 May 6.

Authors

R W Pattie Jr¹, N B Callahan², C Cude-Woods^{1

3}, E R Adamek², L J Broussard⁴, S M Clayton¹, S A Currie¹, E B Dees³, X Ding⁵, E M Engel⁶, D E Fellers¹, W Fox², P Geltenbort⁷, K P Hickerson⁸, M A Hoffbauer¹, A T Holley⁹, A Komives¹⁰, C-Y Liu², S W T MacDonald¹, M Makela¹, C L Morris¹, J D Ortiz¹, J Ramsey¹, D J Salvat¹¹, A Saunders¹², S J Seestrom¹, E I Sharapov¹³, S K Sjue¹, Z Tang¹, J Vanderwerp², B Vogelaar⁵, P L Walstrom¹, Z Wang¹, W Wei¹, H L Weaver¹, J W Wexler³, T L Womack¹, A R Young³, B A Zeck^{1

3}

Affiliations

¹ Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
² Center for Exploration of Energy and Matter and Department of Physics, Indiana University, Bloomington, IN 47408, USA.
³ Triangle Universities Nuclear Laboratory and North Carolina State University, Raleigh, NC 27695, USA.
⁴ Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁵ Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
⁶ West Point Military Academy, West Point, NY 10996, USA.
⁷ Institut Laue-Langevin, Grenoble, France.
⁸ Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125, USA.
⁹ Department of Physics, Tennessee Technological University, Cookeville, TN‎ 38505, USA.
¹⁰ Department of Physics and Astronomy, DePauw University, Greencastle, IN 46135-0037, USA.
¹¹ Department of Physics, University of Washington, Seattle, WA 98195-1560, USA.
¹² Los Alamos National Laboratory, Los Alamos, NM 87545, USA. asaunders@lanl.gov.
¹³ Joint Institute for Nuclear Research, Dubna, Moscow region 141980, Russia.

PMID: 29731449
DOI: 10.1126/science.aan8895

Abstract

The precise value of the mean neutron lifetime, τ_n, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in situ neutron detector, the lifetime reported here [877.7 ± 0.7 (stat) +0.4/-0.2 (sys) seconds] does not require corrections larger than the quoted uncertainties.

Publication types

Research Support, Non-U.S. Gov't