Related papers: Lorentz Violation and Ultrahigh-Energy Photons
Lorentz symmetry breaking at very high energies may lead to photon dispersion relations of the form omega^2=k^2+xi_n k^2(k/M_Pl)^n with new terms suppressed by a power n of the Planck mass M_Pl. We show that first and second order terms of…
Lorentz violation at high energies might lead to non linear dispersion relations for the fundamental particles. We analyze observational constraints on these without assuming any a priori equality between the coefficients determining the…
Recent work has shown that dispersion relations with Planck scale Lorentz violation can produce observable effects at energies many orders of magnitude below the Planck energy M. This opens a window on physics that may reveal quantum…
We place several new limits on Lorentz violating effects, which can modify particles' dispersion relations, by considering the highest energy cosmic rays observed. Since these are hadrons, this involves considering the partonic content of…
We analyze observational constraints from TeV astrophysics on Lorentz violating nonlinear dispersion for photons and electrons without assuming any a priori equality between the photon and electron parameters. The constraints arise from…
We point out that violation of Lorentz invariance affects the interaction of high-energy photons with the Earth's atmosphere and magnetic field. In certain parameter region this interaction becomes suppressed and the photons escape…
Motivated by experimental indications of a significant presence of heavy nuclei in the cosmic ray flux at ultra high energies ($\gtrsim 10^{19} \eV$), we consider the effects of Planck scale suppressed Lorentz Invariance Violation (LIV) on…
From special relativity, photon annihilation process \HepProcess{{\Pgg}{\Pgg}{\to}{\Pep}{\Pem}} prevents cosmic photons with energies above a threshold to propagate a long distance in cosmic space due to their annihilation with low energy…
Lorentz violation (LV) is predicted by some quantum gravity (QG) candidates, wherein the canonical energy-momentum dispersion relation, $E^2=p^2+m^2$, is modified. Consequently, new phenomenons beyond the standard model are predicted.…
Remnant low-energy effects of Planck-scale Lorentz breaking in candidate fundamental theories typically include modified one-particle dispersion relations. Theoretical constraints on such modifications are discussed leading to the exclusion…
We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic…
Some extensions to the Standard Model lead to the introduction of Lorentz symmetry breaking terms, expected to induce deviations from Lorentz symmetry around the Planck scale. A parameterization of effects due to Lorentz invariance…
Ultrahigh energy cosmic rays that produce giant extensive showers of charged particles and photons when they interact in the Earth's atmosphere provide a unique tool to search for new physics. Of particular interest is the possibility of…
Observations of the synchrotron and inverse Compton emissions from ultrarelativistic electrons in astrophysical sources can reveal a great deal about the energy-momentum relations of those electrons. They can thus be used to place bounds on…
If Lorentz violation exists, it will affect the thresholds for pair creation processes. Lorentz-violating operators that change the maximum velocities of charged particles may increase or decrease the extinction rate of gamma-rays moving…
Tiny Lorentz Invariance Violation (LIV) effects, potentially arising from quantum gravity-induced spacetime structures, may also manifest in the proton sector, offering a plausible pathway to test Planck-scale physics through high-energy…
Deviation from standard dispersion relations for electrons and photons in the form of an extra term proportional to an arbitrarily high power of momentum is studied. It is shown that observational constraints lead to a region in the…
Constraints on possible Lorentz symmetry violation (LV) of order E/M_Planck for electrons and photons in the framework of effective field theory (EFT) are discussed. Using (i) the report of polarized MeV emission from GRB021206 and (ii) the…
We postulate in the present paper that the energy-momentum relation is modified for very high energy particles to violate Lorentz invariance and the speed of photon is changed from the light velocity c. The violation effect is amplified, in…
Some solutions to the anomalies of ultra high energy cosmic-ray(UHECR) and TeV $\gamma$-rays require disturbed non-quadratic dispersion relations, which suggest the Lorentz violation. Also, some new theories such as quantum gravity, string…