Constraints on equivalence principle violation from gamma ray bursts

D. J. Bartlett, ∗ D. Bergsdal, 3 H. Desmond, P. G. Ferreira, and J. Jasche Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK Particle and Astroparticle Physics, Department of Physics, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova University Centre, SE 106 91 Stockholm, Sweden