Viewpoint: Positrons Galore /Physics/ by Stephane Coutu,
Institute for Gravitation and the
Cosmos, Departments of Physics and of Astronomy and Astrophysics,
Pennsylvania State University, University Park, PA 16802-6300, USA/ Published
April 3, 2013
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Physics 6, 40 (2013)
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DOI:
10.1103/Physics.6.40
The first results from the space-borne Alpha
Magnetic Spectrometer confirm an unexplained excess of high-energy
positrons in Earth-bound cosmic rays.
Antimatter is rare in the universe today. As far as we know, all relic
antimatter produced in the big bang disappeared long ago in annihilation
reactions with matter particles. What this means is that any antimatter
particles that we can detect in the flux of energetic cosmic rays near
Earth must have been created by “new” sources within our Milky Way
Galaxy. (Antimatter particles from extragalactic sources are also
conceivable, but they are exceedingly unlikely to make it to Earth
before losing all their energy or annihilating.) Because there is a
limited amount of energetic antimatter from space raining down upon the
Earth, antiparticles serve as unique messengers of high-energy phenomena
in the cosmos, or signatures of exotic new physics...
Full article: http://physics.aps.org/articles/v6/40
