Chiral two-body currents in nuclei: Gamow-Teller transitions and neutrinoless double-beta decay

TL;DR

This paper demonstrates that chiral EFT two-body currents significantly affect Gamow-Teller transitions and neutrinoless double-beta decay, providing crucial insights for accurate nuclear matrix element calculations.

Contribution

It introduces the first calculation of the neutrinoless double-beta decay operator based on chiral EFT currents, highlighting the importance of two-body currents.

Findings

Chiral two-body currents cause notable quenching of Gamow-Teller transitions.

Chiral EFT predicts the momentum-transfer dependence in neutrinoless double-beta decay.

Two-body currents significantly impact nuclear matrix element calculations.

Abstract

We show that chiral effective field theory (EFT) two-body currents provide important contributions to the quenching of low-momentum-transfer Gamow-Teller transitions, and use chiral EFT to predict the momentum-transfer dependence that is probed in neutrinoless double-beta decay. We then calculate for the first time the neutrinoless double-beta decay operator based on chiral EFT currents and study the nuclear matrix elements at successive orders. The contributions from chiral two-body currents are significant and should be included in all calculations.