Final state interaction in the pn and nn decay channels of $^4_\Lambda$He

TL;DR

This paper investigates how final state interactions affect the non-mesonic weak decay of the hypernucleus $_\Lambda^4$He, finding that these interactions have a minor impact on the emitted nucleon pair's energy spectrum.

Contribution

It introduces a three-body model to analyze the effects of nucleon interactions and spin symmetries in the decay process of $_\Lambda^4$He, highlighting the limited role of final state interactions.

Findings

Final state interactions have a minor effect on the nucleon energy spectrum.

The spin symmetries influence the final state configurations.

Distortions of emitted nucleons are considered but found to be less significant.

Abstract

We study the effects of final state interactions in the non-mesonic weak decay $\Lambda N \rightarrow nN$ (n is a neutron and N is either a neutron or a proton) of the hypernucleus $_\Lambda^4$He. Using a three-body model the effects of distortion of the interaction of the emitted nucleon pair with the residual nucleus is considered. We also study the influence of the final state interaction between the emitted nucleons using the Migdal-Watson model. The effect of spin symmetries in the final state of the pair is also considered. Based on our calculations, we conclude that final state interactions play a minor role in the kinetic energy spectrum of the emitted nucleon pair.