Halo EFT for ³¹Ne in a spherical formalism

We calculate the electromagnetic properties of the deformed one-neutron halo candidate ³¹Ne using Halo effective field theory (Halo EFT). In this framework, ³¹Ne is bound via a resonant P-wave interaction between the ³⁰Ne core and the valence neutron. We set up a spherical formalism for ³¹Ne in order to calculate the electromagnetic form factors and the E1-breakup strength distribution into the ³⁰Ne-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 ³⁰Ne core enters at next-to-leading order. It can be accounted for by including the J P = 2+ excited state of ³⁰Ne as an explicit field in the effective Lagrangian.