Abstract
We present lattice calculations of the low-lying spectrum of ^{12}C using a simple nucleon–nucleon interaction that is independent of spin and isospin and therefore invariant under Wigner’s SU(4) symmetry. We find strong signals for all excited states up to sim 15 MeV above the ground state, and explore the structure of each state using a large variety of alpha cluster and harmonic oscillator trial states, projected onto given irreducible representations of the cubic group. We are able to verify earlier findings for the alpha clustering in the Hoyle state and the second 2^+ state of ^{12}C. The success of these calculations to describe the full low-lying energy spectrum using spin-independent interactions suggest that either the spin-orbit interactions are somewhat weak in the ^{12}C system, or the effects of alpha clustering are diminishing their influence. This is in agreement with previous findings from ab initio shell model calculations.
Highlights
Wigner SU(4) symmetry is known to be connected to the large-color limit of QCD [11,12]
Nuclear Lattice Effective Field Theory (NLEFT) is an ab initio method where the chiral EFT expansion is combined with Projection Monte Carlo (PMC) simulations [15,16]
We show the results for various irreps that allow us to extract a number of excited states, using alphacluster and shell-model basis states [27]
Summary
In Ref. [1], it was shown that the ground state properties of many light and medium-mass nuclei as well as neutron matter could be well-described by microscopic A-body lattice calculations using a spin- and isospin-independent interaction plus the Coulomb interaction. While our results here are fully microscopic A-body calculations with full correlations to all orders, they are not ab initio in the sense that the nucleon-nucleon interaction is not fitted to nucleon-nucleon scattering data but rather tuned to reproduce the ground state energies of 4He and 12C. These calculations serve as an important comparative benchmark for future ab initio calculations using chiral effective field theory
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
