Constraining neutrino superluminality from searches for sterile neutrino decays

Abstract

Superluminal neutrinos are expected to lose energy due to bremstrauhlung. It is dominated by e+e--pair production if kinematically allowed. The same signature was used in searches for 3-body decays of hypothetical heavy sterile neutrinos. From the absence of these processes in CERN PS191 and CHARM experiments we set upper limits on the neutrino velocity in the energy range from 0.2 GeV to 280 GeV. Our limits are well below the neutrino velocity favored by the recent OPERA results. For energy-independent neutrino velocity the limits obtained in this paper are stronger than those coming from ICARUS experiment and observations of Supernova SN1987a.