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arXiv · 0712.4345

Lorentz-symmetry violating decays in a medium

José F. Nieves·Palash B. Pal
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Abstract

Various decay processes, such as the decay of a spin-1 particle into two photons or the gravitational decay of a spin-1/2 fermion, are forbidden in the vacuum by a combination of requirements, including angular momentum conservation, Lorentz invariance and gauge invariance. We show that such processes can occur in a medium, such as a thermal background of particles, even if it is homogeneous and isotropic. We carry out a model-independent analysis of the vertex function for such processes in terms of a set of form factors, and show that the amplitude can be non-zero while remaining consistent with the symmetry principles mentioned above. The results simulate Lorentz symmetry violating effects, although in this case they arise from completely Lorentz-invariant physics.

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José F. Nieves, Palash B. Pal. 2007-12-28. Lorentz-symmetry violating decays in a medium. https://doi.org/10.1103/physrevd.77.113001

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