Causality violation in e+e− pair production by superluminal neutrinos

Abstract

Pair emission by superluminal neutrinos is shown to be causality violating in the 10–50 GeV range covered by the OPERA experiment. Thus, the energy density of a freely propagating superluminal neutrino current is not affected by energy loss due to e+e− pair creation, in accordance with the unperturbed energy profile observed by ICARUS. Interaction processes involving sub- and superluminal particles give rise to time inversions in the rest frames of the subluminal constituents, resulting in causality violating predetermination. Therefore, kinematic causality constraints in addition to energy-momentum conservation are necessary to exclude causality violation outside the lightcone. Electron-positron pair production by superluminal muon neutrinos is forbidden in the OPERA energy range, as the kinematic constraints on the neutrino frequencies and wave vectors required by causality and energy-momentum conservation cannot simultaneously be satisfied.