The PAMELA Experiment: Preliminary Results after Two Years of Data Taking

PAMELA is a satellite.borne experiment designed to study charged particles in the cosmic radiation. The primary scientific goal is the study of the antimatter component of the cosmic-rays over the largest energy range ever achieved (antiprotons, 80 MeV - 100's GeV; and positrons, 50 MeV - 270 GeV) in order to search for evidence of dark matter particle annihilations. PAMELA is also searching for primordial antinuclei with un-precedent sensitivity, and its precise measurements of the antiparticle energy spectrum together with its precision studies of light nuclei and their isotopes are used to test cosmic. ray propagation models. Moreover, PAMELA is investigating low energy particles in the cosmic radiation which permit to study solar physics and solar modulation during the 24th solar minimum. Finally, the reconstruction of the cosmic ray electron energy spectrum up to several TeV allows a possible contribution from local sources to be studied. PAMELA is housed on.board the Russian Resurs.DK1 satellite, which was launched on June 15th 2006 in an elliptical (350-610 km altitude) orbit with an inclination of 70 degrees. The status of the PAMELA experiment is reviewed, and scientific results after two years in flight are presented. (authors)