We revisit the renormalization prescription for the quark-meson model in an extended mean-field approximation, where vacuum quark fluctuations are included. At a given cutoff scale the model parameters are fixed by fitting vacuum quantities, typically including the sigma-meson mass mσ and the pion decay constant fπ. In most publications the latter is identified with the expectation value of the sigma field, while for mσ the curvature mass is taken. When quark loops are included, this prescription is however inconsistent, and the correct identification involves the renormalized pion decay constant and the sigma pole mass. In the present article we investigate the influence of the parameter-fixing scheme on the phase structure of the model at finite temperature and chemical potential. Despite large differences between the model parameters in the two schemes, we find that in homogeneous matter the effect on the phase diagram is relatively small. For inhomogeneous phases, on the other hand, the choice of the proper renormalization prescription is crucial. In particular, we show that if renormalization effects on the pion decay constant are not considered, the model does not even present a well-defined renormalized limit when the cutoff is sent to infinity.

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We compute the electric form factors of one-neutron halo nuclei with shallow D-wave states up to nextto-leading order and the E2 transition from the S-wave to the D-wave state up to leading order in Halo Effective Field Theory (Halo EFT). The relevant degrees of freedom are the core and the halo neutron. The EFT expansion is carried out in powers of R core /R halo , where R core and R halo denote the length scales of the core and the halo, respectively. We propose a power counting scenario for weakly-bound states in one-neutron Halo EFT and discuss its implications for higher partial waves in terms of universality. The scenario is applied to the 5 2 + first excited state and the 1 2 + ground state of 15 C. We obtain several universal correlations between electric observables and use data for the E2 transition 5 2 + → 1 2 + together with ab initio results from the No-Core Shell Model to predict the quadrupole moment.

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.

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.