PIRSA:09060033  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Recent Results from the ATIC Experiment
Speaker(s): Eun-Suk Seo
Abstract: The balloon-borne Advanced Thin Ionization Calorimeter (ATIC) experiment has measured the cosmic-ray electron spectrum over the energy range from 20 GeV to 3 TeV. The totally active Bismuth Germanate (BGO) calorimeter provides energy measurements with resolution of ~2%. The finely segmented Silicon matrix provides charge measurements with an excellent resolution of ~0.2 e. Below 100 GeV, the ATIC spectrum agrees with previous data and with a calculated spectrum based on a conventional galactic propagation model. Above ~100 GeV the results depart from the calculated spectrum and show an excess electron flux up to about 650 GeV, above which the spectrum drops rapidly. The source of this electron surplus would need to be a previously unidentified and relatively nearby cosmic object within ~1 kilo parsec of the Sun. It could be an astrophysical source, but it might also result from annihilation of dark matter particles. The measurement technique, and the implication of the results will be discussed.
Date: 11/06/2009 - 9:40 am
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