Probes of Lorentz violation in neutrino propagation

Abstract

It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c=[1{+-}(E/M{sub {nu}}{sub QG1})] or [1{+-}(E/M{sub {nu}}{sub QG2}){sup 2}], using data from supernova explosions and the OPERA long-baseline neutrino experiment. Using the SN1987a neutrino data from the Kamioka II, IMB, and Baksan experiments, we set the limits M{sub {nu}}{sub QG1}>2.7(2.5)x10{sup 10} GeV for subluminal (superluminal) propagation and M{sub {nu}}{sub QG2}>4.6(4.1)x10{sup 4} GeV at the 95% confidence level. A future galactic supernova at a distance of 10 kpc would have sensitivity to M{sub {nu}}{sub QG1}>2(4)x10{sup 11} GeV for subluminal (superluminal) propagation and M{sub {nu}}{sub QG2}>2(4)x10{sup 5} GeV. With the current CERN neutrinos to Gran Sasso extraction spill length of 10.5 {mu}s and with standard clock synchronization techniques, the sensitivity of the OPERA experiment would reach M{sub {nu}}{sub QG1}{approx}7x10{sup 5} GeV (M{sub {nu}}{sub QG2}{approx}8x10{sup 3} GeV) after 5 years of nominal running. If the time structure of the super protonmore » synchrotron radio frequency bunches within the extracted CERN neutrinos to Gran Sasso spills could be exploited, these figures would be significantly improved to M{sub {nu}}{sub QG1}{approx}5x10{sup 7} GeV (M{sub {nu}}{sub QG2}{approx}4x10{sup 4} GeV). These results can be improved further if a similar time resolution can be achieved with neutrino events occurring in the rock upstream of the OPERA detector: we find potential sensitivities to M{sub {nu}}{sub QG1}{approx}4x10{sup 8} GeV and M{sub {nu}}{sub QG2}{approx}7x10{sup 5} GeV.« less