The low-down on Ultrahigh Energy Cosmic Rays: experimental results and theoretical puzzles, NPAC (Nuclear/Particle/Astro/Cosmo) Forum, Glennys Farrar, New York University
2009-10-29 21:00 UTC | 4274 Chamberlin
Observed properties of UHECR showers are difficult to reconcile with simulated showers and arrival direction information, and no choice of composition seems compatible with all observations. At the moment, one or more improbable or very improbable statistical fluctuations, or a new physics threshold at about 100 TeV, seem to be the only viable explanations. I will also describe new, much better constraints on the Galactic Magnetic Field. The proposal that a large fraction of UHECRs may come from Centaurus A -- which, at about 3.5 Mpc is the closest plausible source -- can be excluded, unless extragalactic magnetic fields are much larger than generally thought.
