Robust limits on Lorentz violation from gammaray bursts
Abstract
We constrain the possibility of a nontrivial refractive index in free space corresponding to an energydependent velocity of light: c( E) ≃ c_{0}(1  E/ M), where M is a mass scale that might represent effect of quantumgravitational spacetime foam, using the arrival times of sharp features observed in the intensities of radiation with different energies from a large sample of gammaray bursters (GRBs) with known redshifts. We use wavelet techniques to identify genuine features, which we confirm in simulations with artificial added noise. Using the weighted averages of the timelags calculated using correlated features in all the GRB light curves, we find a systematic tendency for more energetic photons to arrive earlier. However, there is a very strong correlation between the parameters characterizing an intrinsic timelag at the source and a distancedependent propagation effect. Moreover, the significance of the earlier arrival times is less evident for a subsample of more robust spectral structures. Allowing for intrinsic stochastic timelags in these features, we establish a statistically robust lower limit: M > 0.9 × 10 ^{16} GeV on the scale of violation of Lorentz invariance.
 Publication:

Astroparticle Physics
 Pub Date:
 July 2006
 DOI:
 10.1016/j.astropartphys.2006.04.001
 arXiv:
 arXiv:astroph/0510172
 Bibcode:
 2006APh....25..402E
 Keywords:

 04.50.+h;
 04.62.+v;
 98.80.Cq;
 Gravity in more than four dimensions KaluzaKlein theory unified field theories;
 alternative theories of gravity;
 Quantum field theory in curved spacetime;
 Particletheory and fieldtheory models of the early Universe;
 Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 18 pages, 4 eps figures