Top hadrons in Lorentz-violating field theory

Brett Altschul

doi:10.1103/physrevd.102.075010

Abstract

If there is Lorentz symmetry violation in the $t$ quark sector of the standard model, changes to particles' dispersion relations might allow for the existence of stable top-flavored hadrons. Observations of the survival of high-energy $\gamma$-rays over astrophysical distances can be used to place one-sided constraints on certain linear combinations of Lorentz violation coefficients in the $t$ sector at the $\sim 10^{-4}$ level of precision.

Highlights

Since the introduction of the special theory of relativity, there has always been interest in understanding whether the Lorentz symmetry of special relativity is exact, or whether it is merely an excellent approximation
Understanding how these two theories can be reconciled into a theory of quantum gravity is probably the greatest remaining challenge in fundamental physics. Despite their puzzling differences, the two basic theories have a number of important features in common. These include a number of spacetime symmetries; both the standard model and general relativity are invariant under rotations, Lorentz boosts, and CPT
The previous bound from [20], based on radiative corrections, can be seen as complementary to the collection of photon survival bounds derived from observations of different sources

Summary

INTRODUCTION

Since the introduction of the special theory of relativity, there has always been interest in understanding whether the Lorentz symmetry of special relativity is exact, or whether it is merely an excellent approximation. The fundamental physics that we currently understand is based on two very different theories, the standard model, describing particle physics, and general relativity, which describes gravitation. The observation of TeV-scale γ-rays reveals information about the processes that might have produced them—typically either inverse Compton scattering, e− þ γ → e− þ γ, involving the upscattering of a lowenergy photon by an exceedingly energetic electron, or neutral pion decay, π0 → γ þ γ The fact that such photons are produced at all tells us things about energy-momentum relations of all the particles that are involved in the reaction. Any kind of decay process that occurs in vacuum and involves one or more massive daughter particles is forbidden by energy-momentum conservation, if all the quanta have their usual Lorentz-invariant dispersion relations.

LORENTZ VIOLATION IN THE MINIMAL SME

PHOTON DECAY INTO TOP-FLAVORED HADRONS

NUMERICAL BOUNDS

CONCLUSIONS