Ground-state electromagnetic moments of calcium isotopes
Abstract
Background: The neutron-rich calcium isotopes have gained particular interest as evidence of closed-shell structures has recently been found in two exotic nuclei, at N =32 and N =34 . Additionally, the study of such neutron-rich systems has revealed new aspects of nuclear forces, in particular regarding the role of three-nucleon forces.
Purpose: We study the electromagnetic properties of Ca isotopes around the neutron number N =32 . Methods: High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the Ca-5143 isotopes. Results: The ground-state magnetic moments of Ca,5149 and quadrupole moments of 47,49,51Ca were measured for the first time, and the 51Ca ground-state spin I = 3 /2 was determined in a model-independent way. Our experimental results are compared with state-of-the-art shell-model calculations using both phenomenological interactions and microscopic interactions derived from chiral effective field theory. Conclusions: The results for the ground-state moments of neutron-rich isotopes are in excellent agreement with predictions of interactions derived from chiral effective field theory including three-nucleon forces. Lighter isotopes illustrate the presence of particle-hole excitations of the 40Ca core in their ground state. Our results provide a critical test of modern nuclear theories, and give direct answer to the evolution of ground-state electromagnetic properties in the Ca isotopic chain across three doubly closed-shell configurations at N =20 , 28, 32 of this unique system.- Publication:
-
Physical Review C
- Pub Date:
- April 2015
- DOI:
- 10.1103/PhysRevC.91.041304
- arXiv:
- arXiv:1504.04474
- Bibcode:
- 2015PhRvC..91d1304G
- Keywords:
-
- 21.10.Ky;
- 21.45.Ff;
- 21.60.Cs;
- 42.62.Fi;
- Electromagnetic moments;
- Three-nucleon forces;
- Shell model;
- Laser spectroscopy;
- Nuclear Experiment;
- Nuclear Theory
- E-Print:
- Accepted as a Rapid Communication in Physical Review C