Precision Measurement of the $^{6}\mathrm{He}$ Half-Life and the Weak Axial Current in Nuclei

Precision Measurement of the ${}^{6}{He}$ Half-Life and the Weak Axial Current in Nuclei

A. Knecht, R. Hong, D. W. Zumwalt, B. G. Delbridge, A. García, P. Müller, H. E. Swanson, I. S. Towner, S. Utsuno, W. Williams, and C. Wrede

Phys. Rev. Lett. 108, 122502 – Published 23 March 2012

Abstract

Studies of ${}^{6}{He}$ beta decay along with tritium can play an important role in testing ab initio nuclear wave-function calculations and may allow for fixing low-energy constants in effective-field theories. Here, we present an improved determination of the ${}^{6}{He}$ half-life to a relative precision of $3 \times 10^{- 4}$ . Our value of $806.89 \pm {0.11}_{stat} {\binom{+ 0.23}{- 0.19}}_{syst} ms$ resolves a major discrepancy between previous measurements. Calculating the statistical rate function we determined the $f t$ value to be ${803.04}_{- 0.23}^{+ 0.26} s$ . The extracted Gamow-Teller matrix element agrees within a few percent with ab initio calculations.

Received 25 October 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.122502

Authors & Affiliations

A. Knecht^1,*, R. Hong¹, D. W. Zumwalt¹, B. G. Delbridge¹, A. García¹, P. Müller², H. E. Swanson¹, I. S. Towner³, S. Utsuno¹, W. Williams^2,†, and C. Wrede^1,‡

¹Department of Physics and Center for Experimental Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA
²Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
³Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA

^*knechta@uw.edu
^†Present address: Department of Physics, Old Dominion University, Norfolk, VA 23529, USA.
^‡Present address: Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA.