Implications of spacetime quantization for theBahcall–Waxman neutrino bound

Abstract

There is growing interest in quantum-spacetime models in whichsmall departures from Lorentz symmetry are governed by thePlanck scale. In particular, several studies have considered thepossibility that these small violations of Lorentz symmetry mayaffect various astrophysical observations, such as theevaluation of the GZK limit for cosmic rays, the interaction ofTeV photons with the far infrared background and the arrivaltime of photons with different energies from cosmologicalsources. We show that the same Planck-scale departures fromLorentz symmetry that led to a modification of the GZK limit also have significant implications for the evaluation of theBahcall–Waxman bound on the flux of high-energy neutrinosproduced by photo–meson interactions.