Addendum: Ultrahigh-energy cosmic-ray bounds on nonbirefringent modified-Maxwell theory

Ultrahigh-energy cosmic-ray bounds on nonbirefringent modified-Maxwell theory

A particularly simple Lorentz-violating modification of the Maxwell theory of photons maintains gauge invariance, CPT, and renormalization. This modified-Maxwell theory, coupled to standard Dirac particles, involves nineteen dimensionless "deformation parameters." Ten of these parameters lead to birefringence and are already tightly constrained by astrophysics. New bounds on the remaining nine nonbirefringent parameters can be obtained from the absence of vacuum Cherenkov radiation for ultrahigh-energy cosmic rays (UHECRs). Using selected UHECR events recorded at the Pierre Auger Observatory a…

New indirect bounds on Lorentz violation in the photon sector

Direct laboratory bounds on the 9 nonbirefringent Lorentz-violating dimensionless parameters of modified-Maxwell theory range from the 10^{-7} level to the 10^{-16} level. The detection of air showers initiated by charged primaries (ultrahigh-energy cosmic-rays) and neutral primaries (TeV gamma-rays) allows us to obtain new indirect bounds ranging from the 10^{-15} level to the 10^{-19} level. Possible physics implications are briefly discussed.

UHECR bounds on Lorentz violation in the photon sector

The aim of this brief review is to present a case study of how astrophysics data can be used to get bounds on Lorentz-violating parameters. For this purpose, a particularly simple Lorentz-violating modification of the Maxwell theory of photons is considered, which maintains gauge invariance, CPT, and renormalization. With a standard spin-one-half Dirac particle minimally coupled to this nonstandard photon, the resulting modified-quantum-electrodynamics model involves nineteen dimensionless "deformation parameters." Ten of these parameters lead to birefringence and are already tightly constrain…

关于D-泡沫大气效应的评论：基于μ子谜题的视角

Remarks on atmospheric effect of D-foam in light of muon puzzle

本文利用弦论量子时空泡沫模型，研究其对超高能宇宙线引发的大气簇射中μ子含量的影响，提出泡沫效应可能导致μ子“过剩”，为解释Auger等实验观测提供量子引力解释。