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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Cosmic rays are predominantly nuclei, in particular protons. However, the less abundant cosmic-ray electrons and positrons are also important probes of open questions in astrophysics and particle physics. The Fermi Gamma Ray Space Telescope, designed to study the high-energy universe with gamma rays, is also an excellent electron and positron detector. Ground-based imaging atmospheric Cherenkov telescopes have also measured cosmic-ray electrons and positrons up to several TeV. PAMELA, Fermi, and AMS have discovered a surprising excess of positrons between 10 GeV and 350 GeV. I will describe these measurements and their implications for astrophysics and particle physics, as well as prospects for future measurements.
