Abstract
We study phenomena predicted by a renormalizable, invariant extension of the standard model that contains higher-dimensional operators and violates Lorentz symmetry explicitly at energies greater than some scale . In particular, we consider the Cherenkov radiation in vacuo. In a rather general class of dispersion relations, there exists an energy threshold above which radiation is emitted. The threshold is enhanced in composite particles by a sort of kinematic screening mechanism. We study the energy loss and compare the predictions of our model with known experimental bounds on Lorentz violating parameters and observations of ultrahigh-energy cosmic rays. We argue that the scale of Lorentz violation (with preserved invariance) can be smaller than the Planck scale, actually as small as . Our model also predicts the Cherenkov radiation of neutral particles.
- Received 17 January 2011
DOI:https://doi.org/10.1103/PhysRevD.83.056010
© 2011 American Physical Society