Pseudo-Dirac neutrinos and relic neutrino matter effect on the high-energy neutrino flavor composition

Journal Article · Wed Feb 05 00:00:00 EST 2025 · Phys.Lett.B

DOI:https://doi.org/10.1016/j.physletb.2025.139306· OSTI ID:2397237

Dev, P.S. Bhupal ^[1]; Machado, Pedro A.N. ^[2]; Martinez-Soler, Ivan ^[3]

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1. Washington U., St. Louis
2. Fermilab
3. Durham U.

We show that if neutrinos are pseudo-Dirac, they can potentially affect the flavor ratio predictions for the high-energy astrophysical neutrino flux observed by IceCube. In this context, we point out a novel matter effect induced by the cosmic neutrino background (CνB) on the flavor ratio composition. Specifically, the active-sterile neutrino oscillations over the astrophysical baseline lead to an energy-dependent flavor ratio at Earth due to the CνB matter effect, which is in principle distinguishable from the vacuum oscillation effect, provided there is an asymmetry between the neutrino and antineutrino number densities, as well as a local CνB overdensity. Considering the projected precision of the 3-neutrino oscillation parameter measurements and improved flavor triangle measurements, we show that the next-generation neutrino telescopes, such as KM3NeT and IceCube-Gen2, can in principle probe the pseudo-Dirac neutrino hypothesis and the CνB matter effect.

• Research Organization: Durham U.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Washington U., St. Louis
• Sponsoring Organization: US Department of Energy
• Grant/Contract Number: 89243024CSC000002
• OSTI ID: 2397237
• Report Number(s): CETUP-2023-022; FERMILAB-PUB-24-0317-T; IPPP/24/35; arXiv:2406.18507; oai:inspirehep.net:2802363
• Journal Information: Phys.Lett.B, Journal Name: Phys.Lett.B Vol. 862
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS