A Theoretical Diagnosis on Light Speed Anisotropy from GRAAL Experiment

The light speed anisotropy, i.e., the variation of the light speed with respect to the direction in an "absolute" reference frame, is a profound issue in physics. The one-way experiment, performed at the GRAAL facility of the European Synchrotron Radiation Facility (ESRF) in Grenoble, reported results on the light speed anisotropy by Compton scattering of laser photons on high-energy electrons. So far, most articles concerned with the GRAAL data have established only the upper bounds on the anisotropy parameters based on available theories. We use a new theory of the Lorentz invariance violation to analyse the available GRAAL data and obtain the stringent upper limit of the order $2.4\times10^{-14}$ on the Lorentz violation parameters. In the meantime, we also can reproduce the allowed light speed anisotropy appearing in the azimuthal distribution of the GRAAL experimental data, and find that the best-fit parameters are compatible with the competitive upper bounds.Comment: 13 pages, 2 figures, final version in journal publicatio

Neutrino speed anomaly as signal of Lorentz violation

We make a reanalysis on the issue of neutrino speed anomaly by taking into account the newly reported data from the ICARUS experiment and other CNGS collaborations. We examine the consequence of the Lorentz violation on the neutrino speed in a new framework of standard model supplement (SMS), and find that the Lorentz violating parameters are constrained at least one order stronger than that of the earlier OPERA report. The combination with other phenomenological considerations puts more stringent constraints on the Lorentz violation of neutrinos.Comment: 14 pages. Significantly improved version with updated analysis on the relevant experiments related to neutrino speed. Matches to the final published versio

Lorentz Violation of the Photon Sector in Field Theory Models

We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely the minimal standard model extension (SME) and the standard model supplement (SMS). From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters, but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients $(k_{AF})^{\alpha}$ of the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrix $\Delta^{\alpha\beta}$ of free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients $(k_F)^{\alpha\beta\mu\nu}$, which are independent from each other in the minimal SME, but are inter-related in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints ($2\sigma$) on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.Comment: 9 pages, no figure, three tables. Final version for journal publicatio