Comparison between Variational Monte Carlo and Shell Model Calculations of Neutrinoless Double Beta Decay Matrix Elements in Light Nuclei

Understand

Benchmark comparisons between many-body methods are performed to assess the ingredients necessary for an accurate calculation of neutrinoless double beta decay matrix elements.

• Shell model and variational Monte Carlo (VMC) calculations are carried out for $A=10$ and $12$ nuclei.
• Different variational wavefunctions are used to evaluate the uncertainties in the {\it ab initio} calculations, finding fairly small differences between the VMC double beta decay matrix elements.
• For shell model calculations, the role of model space truncation, radial wavefunction choices, and short-range correlation are investigated and all found to be important.