Loop-enhanced rate of neutrinoless double beta decay

• Main Authors: Werner Rodejohann, Xun-Jie Xu
• Format: Article
• Language: English
• Published: SpringerOpen 2019-11-01
• Series: Journal of High Energy Physics
• Subjects: Beyond Standard Model; Neutrino Physics
• Online Access: http://link.springer.com/article/10.1007/JHEP11(2019)029

Abstract Neutrino masses can be generated radiatively. In such scenarios their masses are calculated by evaluating a self-energy diagram with vanishing external momentum, i.e. taking only the leading order term in a momentum expansion. The difference between the full self-energy and the mass is experimentally difficult to access, since one needs off-shell neutrinos to observe it. However, massive Majorana neutrinos that mediate neutrinoless double beta decay (0νββ) are off-shell, with the virtuality of order 100 MeV. If the energy scale of the self-energy loop is of the order of this virtuality, the amplitude of double beta decay can be modified by the unsuppressed loop effect. This can have a drastic impact on the interpretation of future observations or limits of the 0νββ decay.