Three-body resonances in pionless effective field theory

TL;DR

This paper uses pionless effective field theory to analyze three-body resonances, finding Efimov states turning into resonances in bosonic systems but no resonances in three-neutron systems at leading order.

Contribution

It introduces an analytical continuation method for the Faddeev equation to study three-body resonances within pionless EFT, providing new insights into Efimov states and neutron systems.

Findings

Efimov states become resonances crossing the threshold in bosonic systems

No three-body resonances or virtual states found in three-neutron systems at leading order

Finite volume analysis supports the absence of resonances in neutron systems

Abstract

We investigate the appearance of resonances in three-body systems using pionless effective field theory at leading order. The Faddeev equation is analytically continued to the unphysical sheet adjacent to the positive real energy axis using a contour rotation. We consider both, the three-boson system and the three-neutron system. For the former, we calculate the trajectory of Borromean three-body Efimov states turning into resonances as they cross the three-body threshold. For the latter, we find no sign of three-body resonances or virtual states at leading order. This result is validated by exploring the level structure of three-body states in a finite volume approach.