12,762 research outputs found
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 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
of the SME are predicted to be zero. There are 15 degrees
of freedom in the Lorentz violation matrix of free
photons of the SMS related with the same number of degrees of freedom in the
tensor coefficients , 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 () 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
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