Interpretation of the cosmic ray positron and antiproton fluxes

by Paolo Lipari (ROMA1)

Monday 27 Feb 2017, 15:00 → 16:30 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

The spectral shape of cosmic ray positrons and antiprotons has been accurately measured in the broad kinetic energy range 1-350 GeV. In the higher part of this range (E > 30 GeV)  the positron/antiproton flux ratio has the approximately constant value 2.04+-0.04, that is consistent with being equal to the ratio e+/pbar calculated for the conventional mechanism of production, where the antiparticles are created as secondaries in the inelastic interactions of primary cosmic rays with interstellar gas.  The positron/antiproton ratio at lower energy is significantly higher but in the entire energy range 1-350 GeV, the flux ratio is consistent with being equal to ratio of the production rates in the conventional mechanism, since the low energy antiprotons production is kinematically suppressed. These results strongly suggest that cosmic ray positrons and antiprotons have a common origin as secondaries in hadronic interactions. This conclusion has broad implications for the astrophysics of cosmic rays in the Galaxy. 

Slides sem-roma1.pdf