Halo EFT for $^{31}$Ne in a spherical formalism

Abstract

We calculate the electromagnetic properties of the deformed one-neutron halo candidate 31 Ne using Halo Effective Field Theory (Halo EFT). In this framework, 31 Ne is bound via a resonant Pwave interaction between the 30 Ne core and the valence neutron. We set up a spherical formalism for 31 Ne in order to calculate the electromagnetic form factors and the E1-breakup strength distribution into the 30 Ne-neutron continuum at leading order in Halo EFT. The associated uncertainties are estimated according to our power counting. In particular, we assume that the deformation of the 30 Ne core enters at next-to-leading order. It can be accounted for by including the J P = 2 + excited state of 30 Ne as an explicit field in the effective Lagrangian.