https://doi.org/10.1140/epja/i2017-12357-7
Regular Article - Theoretical Physics
Uncertainties in constraining low-energy constants from 3H
decay
1
Institut für Kernphysik, Technische Universität Darmstadt, 64289, Darmstadt, Germany
2
ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
3
Department of Physics, University of Tokyo, Hongo, 113-0033, Tokyo, Japan
4
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
* e-mail: pklos@theorie.ikp.physik.tu-darmstadt.de
Received:
17
July
2017
Accepted:
25
July
2017
Published online:
25
August
2017
We discuss the uncertainties in constraining low-energy constants of chiral effective field theory from 3H decay. The half-life is very precisely known, so that the Gamow-Teller matrix element has been used to fit the coupling
of the axial-vector current to a short-range two-nucleon pair. Because the same coupling also describes the leading one-pion-exchange three-nucleon force, this in principle provides a very constraining fit, uncorrelated with the 3H binding energy fit used to constrain another low-energy coupling in three-nucleon forces. However, so far such 3H half-life fits have only been performed at a fixed cutoff value. We show that the cutoff dependence due to the regulators in the axial-vector two-body current can significantly affect the Gamow-Teller matrix elements and consequently also the extracted values for the
coupling constant. The degree of the cutoff dependence is correlated with the softness of the employed NN interaction. As a result, present three-nucleon forces based on a fit to 3H
decay underestimate the uncertainty in
. We explore a range of
values that is compatible within cutoff variation with the experimental 3H half-life and estimate the resulting uncertainties for many-body systems by performing calculations of symmetric nuclear matter.
© SIF, Springer-Verlag GmbH Germany, 2017