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A<sc>bstract</sc> We investigate two-neutrino double beta decay (2νββ) in chiral effective field theory. We find contributions from weak magnetism and double-weak pion-exchange at next-to-leading-order in the chiral power counting. We discuss the impact of the chiral corrections on the electron spectra and find that they should be included in analyses of 2νββdecay that aim to uncover new physics signatures in the electron spectrum. We illustrate this point by revisiting the effect of sterile neutrinos and non-standard charged interactions. We also find that the pion-exchange contributions involve nuclear matrix elements that are related to those appearing in neutrinoless double beta decay (0νββ). We investigate whether the 0νββnuclear matrix elements can be obtained from detailed measurements of the energy spectrum of the outgoing electrons in 2νββtransitions.
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This content will become publicly available on April 1, 2026
Neutrinoless double β decay with light sterile neutrinos: the contact terms
A<sc>bstract</sc> We study neutrinoless double-beta decay in extensions of the Standard Model that includenright-handed neutrino singlets, with massesmsbelow the GeV scale. Generalizing recently developed matching methods, we determine themsdependence of the short-rangenn→ppcouplings that appear to leading order in the chiral effective field theory description of neutrinoless double beta decay. We focus on two scenarios, corresponding to the minimalνSM and left-right symmetric models. We illustrate the impact of our new results in the case of theνSM, showing a significant impact on the neutrinoless double-beta decay half-life whenmsis in the 200–800 MeV range.
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- Award ID(s):
- 2402275
- PAR ID:
- 10590932
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Journal of High Energy Physics
- Volume:
- 2025
- Issue:
- 4
- ISSN:
- 1029-8479
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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