An effective field theory approach to fermionic rotational bands in nuclei

TL;DR

This paper develops an effective field theory for fermionic rotational bands in nuclei, extending previous models to odd-mass nuclei and providing a systematic expansion up to fourth order, with applications to multiple isotopes.

Contribution

It introduces a model-independent effective field theory approach for odd-mass nuclei, expanding the particle-rotor model to higher orders in angular velocity.

Findings

Accurately describes rotational bands in various nuclei.

Provides a systematic expansion with understood breakdown scales.

Demonstrates applicability to multiple isotopes.

Abstract

We extend an effective field theory developed to describe rotational bands in even-even nuclei to the odd-mass case. This organizes Bohr and Mottelson's treatment of a particle coupled to a rotor as a model-independent expansion in powers of the angular velocity of the overall system. We carry out this expansion up to fourth order in the angular velocity and present results for $^{99}$Tc, ${}^{159}$Dy, ${}^{167, 169}$Er, ${}^{167, 169}$Tm, ${}^{183}$W, ${}^{235}$U and ${}^{239}$Pu. In each case, the accuracy and breakdown scale of the effective field theory can be understood based on the single-particle and vibrational energy scales in that nucleus.