Neutrinoless double beta decay rates in the presence of light sterile neutrinos
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| author | Dekens, W. de Vries, J. Castillo, D. Menéndez, J. Mereghetti, E. Plakkot, V. Soriano, P. Zhou, G. |
| author_facet | Dekens, W. de Vries, J. Castillo, D. Menéndez, J. Mereghetti, E. Plakkot, V. Soriano, P. Zhou, G. |
| contents | We investigate neutrinoless double-beta decay ($0νββ$) in minimal extensions of the Standard Model of particle physics where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass terms. We argue that the standard treatment of these scenarios, based on mass-dependent nuclear matrix elements, is missing important contributions to the $0νββ$ amplitude. First, new effects arise from the exchange of neutrinos with very small (ultrasoft) momenta, for which we compute the associated nuclear matrix elements for the decays of ${}^{76}$Ge and ${}^{136}$Xe. These contributions can dominate the $0νββ$ rate in cases with light sterile neutrinos. The ultrasoft terms are also relevant in the more standard scenario of just three light Majorana neutrinos where they lead to a $10\%$ reduction of the total $0νββ$ amplitude. Secondly, we highlight the importance of short-range terms associated with medium-heavy sterile neutrinos and provide explicit formulae that can be used in phenomenological analyses. As examples we discuss impact of these new effects in several explicit scenarios, including a realistic $3+2$ model with two right-handed gauge-singlet neutrinos. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_07993 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Neutrinoless double beta decay rates in the presence of light sterile neutrinos Dekens, W. de Vries, J. Castillo, D. Menéndez, J. Mereghetti, E. Plakkot, V. Soriano, P. Zhou, G. High Energy Physics - Phenomenology Nuclear Theory We investigate neutrinoless double-beta decay ($0νββ$) in minimal extensions of the Standard Model of particle physics where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass terms. We argue that the standard treatment of these scenarios, based on mass-dependent nuclear matrix elements, is missing important contributions to the $0νββ$ amplitude. First, new effects arise from the exchange of neutrinos with very small (ultrasoft) momenta, for which we compute the associated nuclear matrix elements for the decays of ${}^{76}$Ge and ${}^{136}$Xe. These contributions can dominate the $0νββ$ rate in cases with light sterile neutrinos. The ultrasoft terms are also relevant in the more standard scenario of just three light Majorana neutrinos where they lead to a $10\%$ reduction of the total $0νββ$ amplitude. Secondly, we highlight the importance of short-range terms associated with medium-heavy sterile neutrinos and provide explicit formulae that can be used in phenomenological analyses. As examples we discuss impact of these new effects in several explicit scenarios, including a realistic $3+2$ model with two right-handed gauge-singlet neutrinos. |
| title | Neutrinoless double beta decay rates in the presence of light sterile neutrinos |
| topic | High Energy Physics - Phenomenology Nuclear Theory |
| url | https://arxiv.org/abs/2402.07993 |