A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization

TL;DR

This paper derives new, significantly tighter constraints on Lorentz invariance violation in photon physics using gamma-ray burst polarization data, improving previous bounds by over five orders of magnitude.

Contribution

It introduces an improved method for estimating redshift and applies polarization observations to set the most stringent limits on dimension 5 Lorentz violation in effective field theory.

Findings

New upper limit on Lorentz violating parameter || of 2.4 x 10^{-15}

Constraint on the standard model extension parameter k^{(5)}_{(V)00}  4.2 x 10^{-34} GeV^{-1}

Constraints exceed previous bounds from Crab Nebula observations

Abstract

Constraints on possible Lorentz invariance violation (LIV) to first order in $E/M_{\rm Planck}$ for photons in the framework of effective field theory (EFT) are discussed, taking cosmological factors into account. Then, using the reported detection of polarized soft $\gamma$-ray emission from the $\gamma$-ray burst GRB041219a that is indicative of an absence of vacuum birefringence, together with a very recent improved method for estimating the redshift of the burst, we derive constraints on the dimension 5 Lorentz violating modification to the Lagrangian of an effective local QFT for QED. Our new constraints are more than five orders of magnitude better than recent constraints from observations of the Crab Nebula. We obtain the upper limit on the Lorentz violating dimension 5 EFT parameter $|\xi|$ of $2.4 \times 10^{-15}$, corresponding to a constraint on the dimension 5 standard model extension parameter, $k^{(5)}_{(V)00} \le 4.2 \times 10^{-34}$ GeV$^{-1}$.