The Latest Results from the Alpha Magnetic Spectrometer

The Alpha Magnetic Spectrometer (AMS) is a 15-nation project on the International Space Station (ISS). Following a 16-year period of construction and testing and a precursor flight on the Space Shuttle in 1998, AMS was installed on the ISS on May 19, 2011. AMS is a precision particle physics magnetic spectrometer. Since its installation on the ISS, it has collected more than 140 billion cosmic rays. Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons and light nuclei as well as their ratios show several unexpected and intriguing features. The new AMS results on the positron flux reveal a new source of high energy positrons. Surprisingly, in this rigidity range the spectral indices of cosmic ray nuclei experience progressive hardening over the rigidity interval of few hundred GV. AMS continues studies of complex antimatter candidates with stringent detector verification and collection of additional data.