Related papers: Laboratory Bounds on Electron Lorentz Violation
A conformally invariant hidden sector is considered, with a scalar operator $O$ of low dimension that couples to the electro-weak gauge bosons of the Standard Model, via terms such as $O F^{\mu\nu}F_{\mu\nu}$. By examining single photon…
The tiny modification of dispersion relation induced by Lorentz violation (LV) is an essential issue in quantum gravity (QG) theories, which can be magnified into significant effects when dealing with astrophysical observations at high…
The recently discovered Higgs particle with a mass near $126$ GeV presents new opportunities to explore Lorentz violation. Ultra-high-energy cosmic rays are one of the most sensitive testing grounds for Lorentz symmetry, and can be used to…
Most current models of Lorentz symmetry violation (LSV) at the Planck scale involve power-like extrapolations of the Lorentz-beaking term down to accelerator and even much lower energies. It is therefore assumed that no intermediate energy…
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…
Astrophysical scenarios provide a unique opportunity to test the possible signatures of Lorentz Invariance Violation (LIV) due to the high energies and the very long distances they involve. An isotropic correction to the photon dispersion…
This presentation discusses some of the signals for Lorentz violation potentially observable in atomic spectroscopy and clock-comparison experiments. The emphasis of the discussion is on how the angular-momentum quantum numbers of the…
The Standard Model cannot explain the dominance of matter over anti-matter in our universe. This imbalance indicates undiscovered physics that violates combined CP symmetry. Many extensions to the Standard Model seek to explain the…
Working in the context of a Lorentz-violating extension of the standard model we show that estimates of Lorentz symmetry violation extracted from ultra-high energy cosmic rays beyond the Greisen-Kuzmin-Zatsepin (GZK) cutoff allow for…
We discuss some of the tests of Lorentz symmetry made possible by astrophysical observations of ultrahigh energy cosmic rays, gamma-rays, and neutrinos. These are among the most sensitive tests of Lorentz symmetry violation because they are…
Forbidden (slow) beta decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and reinterpret the only two relevant…
We point out that equivalence principle violations, while not dynamically equivalent, produce the same kinematical effects as Lorentz invariance violations for particle processes in a constant gravitational potential. This allows us to…
Recently, the laser experiments BMV and GammeV, searching for light shining through walls, have published data and calculated new limits on the allowed masses and couplings for axion-like particles. In this note we point out that these…
The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ESRF's GRAAL facility constrains such…
A general theoretical framework that incorporates possible CPT and Lorentz violation in an extension of the standard model and in quantum electrodynamics has been developed over the last decade. The framework originates in the idea that CPT…
Evidence on the violation of Lorentz symmetry arises from the observation of cosmic rays with energies beyond the GZK cutoff, $E_{GZK} \simeq 4 \times 10^{19} eV$, from the apparent transparency of the Universe to the propagation of high…
Lorentz symmetry is a cornerstone of both the General relativity and Standard Model and its experimental verification deepens our understanding of nature. This paper focuses on the investigation of Lorentz violations with the context of…
A non-vanishing vacuum expectation value for an antisymmetric tensor field leads to the violation of Lorentz invariance on the brane. This violation is controlled by the $\theta_{\mu \nu}$ parameter, which has a dimension of inverse mass…
We consider Lorentz violation in supersymmetric extensions of the standard model. We perform a spurion analysis to show that, in the simplest natural constructions, the resulting supersymmetry-breaking masses are tiny. In the process, we…
We calculate the rates for lepton number violating processes via the exchange of the Z' boson occuring in top-color assisted technicolor. The current experimental limits on muon electron conversion in Ti nuclei allow for a mass of the new…