Synopsis: Earth’s Magnetic Field Aids Study of Cosmic-Ray Puzzle

Synopsis: Earth’s Magnetic Field Aids Study of Cosmic-Ray Puzzle
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.108.011103

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope measured the combined electron and positron spectrum from 7GeV to 1 tera-electron-volt, while PAMELA measured just the electron spectrum from 1 to 625GeV. Both experiments agreed with the first PAMELA results, though neither measured positrons separately. Now the Fermi LAT Collaboration reports in Physical Review Letters they have separately measured both the electron and positron spectra from 20 to 200GeV, including the first measurement of the absolute positron spectrum above 50GeV and the first determination of the positron-to-electron ratio above 100GeV.

See: http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.108.011103
.