Sunday, November 25, 2007



"I have shown here that there exist relativistic theories in which the GZK cutoff is shifted significantly upward (enough to explain the cosmic-ray puzzle) but there is no preferred class of inertial observers."

~ Giovanni Amelino-Camelia, "Kinematical solution of the UHE-cosmic-ray puzzle without a preferred class of inertial observers", Int.J.Mod.Phys. D12 (2003) 1211-1226, astro-ph/0209232, p. 7


"What could instead accomodate exactly the situation where there is no GZK anomaly but we do find anomalous in vacua despersion? Well [...] you basically could go to the direction I prososed a few years ago, which is allow for departures from Lorentz symmetry but without the emergence of a preferred frame [...] No preferred frame. These turn out to be a much softer class [..] of departures from standard Poincare symmetry [...] They are unable [...] to provide an observably large GZK threshold anomaly.

Despite of what is said in many Doubly Special Relativity papers [...] That's not possible."

~ Giovanni Amelino-Camelia, talk given at the workshop on Experimental Search for Quantum Gravity, pirsa:07110057, min. 26:23



    That theory could work and should work doesn't mean that theory will work. If theory doesn't work versus observation, it's wrong.

  2. So this means that DSR is dead?

  3. No, it means that a modification of the standard model which preserves observer independence and which becomes important at Planckian energies can not cause a significant shift in thresholds that are at a GeV in the center of mass frame.

  4. BTW, Amelino-Camelia is in this week's Nature (450, 6 December 2007, p 801-803): Relativity: Still special.

    Best, Stefan


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