The PAMELA detector was launched to measure the amount of these particles in cosmic rays, which the International Space Station’s Alpha Magnetic Spectrometer detected a large fraction of in the 250-275 GeV range. These particles are the rarer of the two particles which interact during Bhabha scattering, and these particles produce 511 keV gamma rays upon (*) annihilation. A proton decays into a neutron, a neutrino, and one of these (10[1])particles (10[1])in a process which is exploited in a technique that uses fluorodeoxyglucose for medical imaging. Carl Anderson first observed this particle in 1932, in the first experimental confirmation of the existence of antimatter. For 10 points, what particles observed in PET scans are the antiparticle to the electron? ■END■ (10[1])