Studies of 6He 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 6He half-life to a relative precision of 3x10^(-4). Our
value of 806.89 \pm 0.11(stat)^{+0.23}_{-0.19}(syst) ms resolves a major
discrepancy between previous measurements. Calculating the statistical rate
function we determined the ft-value to be 803.04 ^{+0.26}_{-0.23} s. The
extracted Gamow-Teller matrix element agrees within a few percent with
ab-initio calculations.Comment: 5 pages, 2 figures, published in Physical Review Letter

Delbridge, B. G.

Garcia, A.

Hong, R.

Knecht, A.

Mueller, P.

Swanson, H. E.

Towner, I. S.

Utsuno, S.

Williams, W.

Wrede, C.

Zumwalt, D. W.

Physical Review Letters

English

arXiv

A. Knecht

R. Hong

D. W. Zumwalt

B. G. Delbridge

A. García

P. Müller

H. E. Swanson

I. S. Towner

S. Utsuno

W. Williams

C. Wrede

Crossref

Precision Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>6</mml:mn></mml:mmultiscripts></mml:math>Half-Life and the Weak Axial Current in Nuclei

Background: The β decays of 3H and 6He can play an important role in testing nuclear wave-function calculations and fixing low-energy constants in effective-field theory approaches. However, there exists a large discrepancy between previous measurements of the 6He half-life. Purpose: Our measurement aims at resolving this long-standing discrepancy in the 6He half-life and providing a reliable ft value and Gamow-Teller matrix element for comparison with theoretical ab initio calculations. Method: We measured the 6He half-life by counting the β-decay electrons with two scintillator detectors operating in coincidence. Results: The measured 6He half-life is 806.89±0.11 stat-0.19+0.23syst ms corresponding to a relative precision of 3×10-4. Calculating the statistical rate function we determined the ft value to be 803.04-0.23+0.26 s. Conclusions: Our result resolves the previous discrepancy by providing a higher-precision result with careful analysis of potential systematic uncertainties. The result provides a reliable basis for future precision comparisons with ab initio calculations. © 2012 American Physical Society

García, A.

Müller, P.

Williams, William

Smith College: Smith ScholarWorks