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arXiv · 2008.06588

Ab initio neutrinoless double-beta decay matrix elements for 48Ca, 76Ge, and 82Se

A. Belley·C. G. Payne·S. R. Stroberg·T. Miyagi·J. D. Holt
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Abstract

We calculate basis-space converged neutrinoless $\beta \beta$ decay nuclear matrix elements for the lightest candidates: 48Ca, 76Ge and 82Se. Starting from initial two- and three-nucleon forces, we apply the ab initio in-medium similarity renormalization group to construct valence-space Hamiltonians and consistently transformed $\beta \beta$-decay operators. We find that the tensor component is non-negligible in 76Ge and 82Se, and resulting nuclear matrix elements are overall 25-45% smaller than those obtained from the phenomenological shell model. While a final matrix element with uncertainties still requires substantial developments, this work nevertheless opens a path toward a true first-principles calculation of neutrinoless $\beta \beta$ decay in all nuclei relevant for ongoing large-scale searches.

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A. Belley, C. G. Payne, S. R. Stroberg, T. Miyagi, J. D. Holt. 2020-08-14. Ab initio neutrinoless double-beta decay matrix elements for 48Ca, 76Ge, and 82Se. https://doi.org/10.1103/physrevlett.126.042502

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