Sep 12 – 16, 2016
Europe/Zurich timezone
There is a live webcast for this event.

Measurement of the Proton and Helium Flux in Cosmic Rays with the Alpha Magnetic Spectrometer: Results and Interpretations.

Sep 12, 2016, 2:00 PM
40/S2-D01 - Salle Dirac (CERN)

40/S2-D01 - Salle Dirac


Show room on map
Oral Contributions Cosmic rays Cosmic rays


Nicola Tomassetti (Perugia University & INFN- Perugia)


We present a precision measurement of the cosmic-ray proton flux at rigidity from 1 GV to 1.8 TV and the helium flux at rigidity from 2 GV to 3 TV. The measurement is based on the data collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The two fluxes are found to progressively harden at rigidities larger than 100 GV, while the proton-to-helium ratio is found to steadily decrease with rigidity.
At rigidity above 45 GV, the ratio is remarkably well described by a single power law, with spectral index 0.077 +/- 0.007. We discuss some possible interpretations of these results in terms of astrophysical models of cosmic-ray acceleration and propagation.

Primary author

Nicola Tomassetti (Perugia University & INFN- Perugia)

Presentation materials