Constraining neutrino superluminality from searches for sterile neutrino decays

TL;DR

This paper uses experimental searches for sterile neutrino decays to set upper limits on neutrino superluminality, constraining theories that suggest neutrinos travel faster than light within a broad energy range.

Contribution

It provides the first comprehensive limits on neutrino superluminality based on sterile neutrino decay searches from CERN PS191 and CHARM experiments, surpassing previous bounds.

Findings

Limits on neutrino velocity are below the level suggested by OPERA.

Constraints are stronger than those from ICARUS and SN1987a.

Energy-independent neutrino velocity is strongly constrained.

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.