MG15 - Talk detail

Back to previous page

 Participant

Institution

Session

Accepted

Order

Time

Talk

Title

Abstract

Lorentz symmetries represent one of the cornerstones of modern physics, and yet independent approaches aiming at combining general relativistic with quantum effects often imply some form of departures from them. According to the simplest models, particles having different energies emitted at the same time from a given source should be detected at different times from a far-away detector, thereby producing a phenomenon of in-vacuo dispersion with a linear correlation between the time of observation and particles’ energy. Given that, the search for energy-dependent time lags in gamma-ray bursts (GRB) has gradually become a standard way to make tests of fundamental physics and also look for the first signatures of the sought-after quantum theory of gravity. Most of the current studies, considering a single GRB or just the most energetic photon for each GRB analysed, allowed to set very tight constraints on the relevant scale, usually believed to be close to the Planck mass. However, due to the rather poor understanding of the spectral evolution of GRBs, statistical analyses over collections of GRBs would provide more reliable outcomes. Here we test in-vacuo dispersion by analysing all the photons with energy at the emission greater than 5 GeV emitted from 7 GRBs observed by Fermi-LAT. Remarkably, we find preliminary evidence of in-vacuo-dispersion-like spectral lags consistently with what has been noticed by some recent studies which, though, had focused only on the energy range above 40 GeV.

Pdf file

Back to previous page