Quadrupole dynamics of carbon isotopes and 10Be

TL;DR

This paper demonstrates that the ratio of neutron to proton quadrupole transition matrix elements in carbon isotopes and 10Be is well-converged in ab initio calculations, providing a new tool for understanding nuclear deformation.

Contribution

It introduces the first use of the Mn/Mp ratio as a robust, converged observable in ab initio no-core shell model studies of nuclear quadrupole dynamics.

Findings

Mn/Mp ratio compares well with experimental data

Provides new insights into nuclear quadrupole response

First demonstration of convergence for this ratio in ab initio models

Abstract

Electric quadrupole (E2) moments and transitions provide measures of nuclear deformation and related collective structure. However, matrix elements of the E2 operator are sensitive to the nuclear wave function at large distances and are poorly convergent within the ab initio no-core shell model approach. We demonstrate for the first time that the ratio of neutron to proton quadrupole transition matrix elements, Mn/Mp, is well-converged in the ab initio no-core shell model and provides a new and robust tool for comparing with experimental results. We find that our parameter-free results for Mn/Mp for the carbon isotopes and 10Be compare well with experiment, where available, and offer new insight into the quadrupole dynamics of nuclear response.