Halo EFT for \(^{31}\)Ne in a spherical formalism

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 \(P\)-wave 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.