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Heavy sterile neutrinos can be produced in core-collapse supernovae (CCSNe), which are superb particle generators because of their high densities and temperatures. If the sterile neutrinos are long-lived, these may be produced inside the supernova core and escape the stellar envelope, later decaying into SM particles like photons and neutrinos. In this work, we first improve the original analytical calculation of the γ-ray fluxes from decays. We then revisit the bounds on the sterile neutrino parameter space from the non-observation of γ -rays from SN1987A by the Solar Maximum Mission (SMM) and constraints from the diffuse γ -ray background arising from sterile neutrino decays. We find that the constraints arising from both the SMM data and the diffuse γ -ray background are weaker than those that have previously appeared in the recent literature. Finally, we study the sensitivity of several present and near-future γ -ray telescopes such as e-ASTROGAM and Fermi-LAT, assuming a nearby future galactic CCSN. We show that future observations can probe mixing angles as low as |Uτ/μ4|2∼ 5 × 10-17.
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Low-energy supernovae bounds on sterile neutrinos
Abstract Sterile neutrinos can be produced through mixing with active neutrinos in the hot, dense core of a core-collapse supernova (SN). The standard bounds on the active-sterile mixing (sin2θ) from SN arise from SN1987A energy-loss, requiringEloss< 1052erg. In this work, we discuss a novel bound on sterile neutrino parameter space arising from the energy deposition through its decays inside the SN envelope. Using the observed underluminous SN IIP population, this energy deposition is constrained to be below ∼ 1050erg. Focusing on sterile neutrino mixing only with tau neutrino, for heavy sterile massesmsin the range 100 – 500 MeV, we find stringent constraints on sin2θτreaching two orders of magnitude lower than those from the SN1987A energy loss argument, thereby probing the mixing angles required for Type-I seesaw mechanism. Similar bounds will also be applicable to sterile mixing only with muons (sin2θμ).
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- Award ID(s):
- 2209420
- PAR ID:
- 10632988
- Publisher / Repository:
- IOP Science
- Date Published:
- Journal Name:
- Journal of Cosmology and Astroparticle Physics
- Volume:
- 2025
- Issue:
- 03
- ISSN:
- 1475-7516
- Page Range / eLocation ID:
- 052
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1088/1475-7516/2025/03/052
