Atmospheric Sterile Neutrinos

Abstract

We study production of sterile neutrinos in the atmosphere and their detection at Super-Kamiokande. A sterile neutrino in the mass range $1\mathrm{MeV}\lesssim M_N\lesssim 105\mathrm{MeV}$ is produced by muon or pion decay, and decays to an electron-positron pair and an active neutrino. Such a decay of the sterile neutrino leaves two electron-like Cherenkov rings in the detector. We estimate the sterile neutrino flux from the well-established active neutrino fluxes and study the number of the decay events in the detector. The upper bounds for the active-sterile mixings are obtained by comparing the $2e$-like events from the sterile neutrino decays and the observed data by Super-Kamiokande. The upper bound for the muon type mixing ${\Theta }_{\mu }$ is found to be $|{\Theta }_{\mu }{|}^2\lesssim 5\times 10^{-5}$ for $20\mathrm{MeV}\lesssim M_N\lesssim 80\mathrm{MeV}$, which is significantly loosened compared to the previous estimation. We demonstrate that the opening angle and the total energy of the rings may serve as diagnostic tools to discover the sterile neutrinos in further data accumulation and future upgraded facilities. The directional asymmetry of the events is a sensitive measure of the diminishment of the sterile neutrino flux due to the decays on the way to the detector.

23 pages, 14 figures; a comment on the active-sterile oscillation is added (v2)

References in corpus (8)

• How to find neutral leptons of the nuMSM?
• The nuMSM, leptonic asymmetries, and properties of singlet fermions
• Sterile neutrino dark matter as a consequence of nuMSM-induced lepton asymmetry
• On the hadronic contribution to sterile neutrino production
• Baryon Asymmetry of the Universe in the NuMSM
• Experimental bounds on sterile neutrino mixing angles
• Mixing of Active and Sterile Neutrinos
• Kinetic Equations for Baryogenesis via Sterile Neutrino Oscillation

Cited by in corpus (11)

• A facility to Search for Hidden Particles at the CERN SPS: the SHiP physics case
• Heavy neutrino search in accelerator-based experiments
• New constraints on Heavy Neutral Leptons from Super-Kamiokande data
• Searches for Atmospheric Long-Lived Particles
• Effects of Long-lived 10 MeV Scale Sterile Neutrino on Primordial Elemental Abundances and Effective Neutrino Number
• Lepton Universality in the $\nu$MSM
• Searching for light long-lived neutralinos at Super-Kamiokande
• Atmospheric axion-like particles at Super-Kamiokande
• Sterile neutrino dark matter with dipole interaction
• Testing Heavy Neutral Leptons in Cosmic Ray Beam Dump experiments
• Probing heavy neutrinos in the COMET experiment