Efimov physics with $1/2$ spin-isospin fermions

TL;DR

This paper investigates Efimov physics in systems of spin-isospin fermions, focusing on universal behaviors near the unitary limit and analyzing three- and four-nucleon systems using potential models.

Contribution

It explores universal properties of few-fermion systems with spin-isospin symmetry near the unitary limit using potential models, emphasizing three- and four-nucleon correlations.

Findings

Evidence of universal behavior in three- and four-nucleon systems.

Behavior of the first excited state varies near the unitary limit.

Dependence of low-energy observables on three-body force range.

Abstract

The structure of few-fermion systems having $1/2$ spin-isospin symmetry is studied using potential models. The strength and range of the two-body potentials are fixed to describe low energy observables in the angular momentum $L=0$ state and spin $S=0,1$ channels of the two-body system. Successively the strength of the potentials are varied in order to explore energy regions in which the two-body scattering lengths are close to the unitary limit. This study is motivated by the fact that in the nuclear system the singlet and triplet scattering lengths are both large with respect to the range of the interaction. Accordingly we expect evidence of universal behavior in the three- and four-nucleon systems that can be observed from the study of correlations between observables. In particular we concentrate in the behavior of the first excited state of the three-nucleon system as the system moves away from the unitary limit. We also analyze the dependence on the range of the three-body force of some low-energy observables in the three- and four-nucleon systems.