nucl-ex digest · Jan 19, 2021

Detailed study of the decay of 32Ar

In an experiment performed at the SPIRAL1 facility of GANIL, the beta decay of 32Ar has been studied by means of the "Silicon Cube" device associated with germanium clover detectors from the EXOGAM array. Beta-delayed protons and gamma rays have been observed and allowed the determination of all relevant decay branches. The Gamow-Teller strength distribution is compared to shell-model calculations and excellent agreement is found. The Fermi strength is inline with expectations. A quasi-complete decay scheme of 32Ar is established.

nucl-exEPJA(2021)·5 citations

02*

The relevance of pion-exchange contributions versus contact terms in the chiral effective field theory description of nucleon-nucleon scattering

H. Alanazi🇺🇸 · R. Machleidt (University of Idaho)

The standard way to demonstrate the relevance of chiral symmetry for the NN interaction is to consider higher partial waves of NN scattering which are controlled entirely by chiral pion-exchanges (since contacts vanish). However, in applications of NN-potentials to nuclear structure and reactions, the lower partial waves are the important ones, making the largest contributions. Lower partial waves are sensitive to the short-range potential, and so, when the short-range contacts were to dominate over the chiral pion-contributions in lower partial waves, then the predictions from "chiral potentials" would have little to do with chiral symmetry. To address this issue, we investigate systematically the role of the (chiral) one- and two-pion exchanges, on the one hand, and the effect of the contacts, on the other hand, in the lower partial waves of NN scattering. We are able to clearly identify the signature of chiral symmetry in lower partial waves. Our study has also a pedagogical spin-off as it demonstrates in detail how the reproduction of the lower partial-wave phase shifts comes about from the various ingredients of the theory.

↳ nucl-thnucl-exFew Body Syst.(2021)·26 citations