# Neutrino Pair Cerenkov Radiation for Tachyonic Neutrinos

Jentschura, Ulrich D.  (Department of Physics, Missouri University of Science and Technology, Rolla, MO 65409, USA) (MTA-DE Particle Physics Research Group, P.O. Box 51, Debrecen 4001, Hungary) ; Nándori, István (MTA-DE Particle Physics Research Group, P.O. Box 51, Debrecen 4001, Hungary)

12 November 2017

Abstract: The emission of a charged light lepton pair by a superluminal neutrino has been identified as a major factor in the energy loss of highly energetic neutrinos. The observation of PeV neutrinos by IceCube implies their stability against lepton pair Cerenkov radiation. Under the assumption of a Lorentz-violating dispersion relation for highly energetic superluminal neutrinos, one may thus constrain the Lorentz-violating parameters. A kinematically different situation arises when one assumes a Lorentz-covariant, space-like dispersion relation for hypothetical tachyonic neutrinos, as an alternative to Lorentz-violating theories. We here discuss a hitherto neglected decay process, where a highly energetic tachyonic neutrino may emit other (space-like, tachyonic) neutrino pairs. We find that the space-like dispersion relation implies the absence of a ${q}^{2}$ threshold for the production of a tachyonic neutrino-antineutrino pair, thus leading to the dominant additional energy loss mechanism for an oncoming tachyonic neutrino in the medium-energy domain. Surprisingly, the small absolute values of the decay rate and energy loss rate in the tachyonic model imply that these models, in contrast to the Lorentz-violating theories, are not pressured by the cosmic PeV neutrinos registered by the IceCube collaboration.

Published in: Advances in High Energy Physics 2017 (2017) 9850312