Constraints on Neutrino Velocities Revisited

TL;DR

This paper reevaluates constraints on superluminal neutrino velocities by calculating decay widths and energy loss rates using different approaches, confirming previous results and analyzing experimental bounds from OPERA, Super-Kamiokande, and IceCube.

Contribution

It provides a comprehensive calculation of neutrino decay and energy loss rates for superluminal neutrinos using both direct and virtual Z-boson approaches, extending previous analyses.

Findings

Confirmed Cohen-Glashow results for low-energy neutrinos

Derived general decay width and energy loss formulas

Analyzed constraints from multiple neutrino experiments

Abstract

With a minimally modified dispersion relation for neutrinos, we reconsider the constraints on superluminal neutrino velocities from bremsstrahlung effects in the laboratory frame. Employing both the direct calculation approach and the virtual Z-boson approach, we obtain the generic decay width and energy loss rate of a superluminal neutrino with general energy. The Cohen-Glashow's analytical results for neutrinos with a relatively low energy are confirmed in both approaches. We employ the survival probability instead of the terminal energy to assess whether a neutrino with a given energy is observable or not in the OPERA experiment. Moreover, using our general results we perform systematical analyses on the constraints arising from the Super-Kamiokande and IceCube experiments.