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| Main Authors: | , |
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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2412.10101 |
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| _version_ | 1866915904562921472 |
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| author | Bertuzzo, Enrico Frigerio, Michele |
| author_facet | Bertuzzo, Enrico Frigerio, Michele |
| contents | Massive sterile neutrinos, also known as heavy neutral leptons, can have a mixing with active neutrinos, $θ$, as well as a dipole coupling to the photon, $d$. We study the interplay between these two portals, considering the production from meson decays of sterile neutrinos with mass $0.1$ GeV $\lesssim M_N \lesssim 10$ GeV, at beam-dump facilities such as NA62 and SHiP, and at the FASER2 experiment. These sterile neutrinos can be long-lived and decay into a photon in a distant detector, via the dipole operator. We find that all these experiments will be sensitive to values of $d$ which are presently unconstrained. The experimental reach varies strongly with the mass $M_N$ and the mixing $θ$, and one observes specific correlations with the flavour of active neutrinos. The SHiP experiment will mark a jump in sensitivity: (i) it will probe a sterile dipole as small as $d\sim 10^{-8}$ GeV$^{-1}$, thus testing new physics well above the electroweak scale; (ii) it may detect the active-sterile dipole to the level predicted by electroweak loops, if $θ$ is close to the present bound. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_10101 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Two portals to GeV sterile neutrinos : dipole versus mixing Bertuzzo, Enrico Frigerio, Michele High Energy Physics - Phenomenology Massive sterile neutrinos, also known as heavy neutral leptons, can have a mixing with active neutrinos, $θ$, as well as a dipole coupling to the photon, $d$. We study the interplay between these two portals, considering the production from meson decays of sterile neutrinos with mass $0.1$ GeV $\lesssim M_N \lesssim 10$ GeV, at beam-dump facilities such as NA62 and SHiP, and at the FASER2 experiment. These sterile neutrinos can be long-lived and decay into a photon in a distant detector, via the dipole operator. We find that all these experiments will be sensitive to values of $d$ which are presently unconstrained. The experimental reach varies strongly with the mass $M_N$ and the mixing $θ$, and one observes specific correlations with the flavour of active neutrinos. The SHiP experiment will mark a jump in sensitivity: (i) it will probe a sterile dipole as small as $d\sim 10^{-8}$ GeV$^{-1}$, thus testing new physics well above the electroweak scale; (ii) it may detect the active-sterile dipole to the level predicted by electroweak loops, if $θ$ is close to the present bound. |
| title | Two portals to GeV sterile neutrinos : dipole versus mixing |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2412.10101 |