The p-He cross section measurement: a physics case from cosmic rays

The interpretation of galactic cosmic ray data requires not only the correct modeling of their sources and of the turbulence spectrum of the galactic magnetic field,  but also the  knowledge of the cross sections that regulate the production and destruction of the particles interacting with the gas of the interstellar medium.
 For many cosmic species, these cross section data are scarce when not missing completely. 

 Specifically, the  antiprotons propagating in the Galaxy are of secondary origin, 
produced by the scattering of cosmic proton and helium nuclei off the  hydrogen and helium  that are present in the interstellar medium. The only measured antiproton production cross section is the proton-proton one while all the reactions involving helium have no laboratory data in the antiproton energy range explored by current experiments.   It is at present of particular interest the experimental study of the antiproton flux in the energy range from about  one  GeV up to hundreds of GeV.  The current empirical modeling of those cross sections induces an uncertainty of about  30-40\%  in the prediction of the antiproton flux which could seriously limit the interpretation of the data collected in space, now provided by AMS-02 with a much smaller error.

 The accurate knowledge and prediction of the cosmic antiproton flux is not only useful
to the understanding of the origin and propagation of galactic cosmic
rays, but also to the indirect dark matter searches. Indeed, the secondary
 antiproton flux acts as a background to a possible dark matter signal in the observed antiproton flux. Dark matter can be indirectly searched also in cosmic positrons, antideuterons and gamma-rays, for which similar problems due to cross section data hold. 

In order to favor the discussion about the opportunity of a dedicated measurement of the p + He —> antiproton + X cross section - as well as positrons, gamma-rays and antideuterons in the final state - we are organizing a meeting in:

                                Torino - July 6 and 7, 2015 

in collaboration with the Torino University and INFN.
 The main idea of the workshop is to favor brainstorming among the
participants.
 The format of the meeting is intended to be informal. 
All the people aiming at giving a talk are warmly welcome.
 It is particularly encouraged the participation of the experimental colleagues and collaborations with expertise and interest in the field. Logistics: the meeting will be held at the                   Molecular Biology Center,  MBC, via Nizza 52, TORINO at a walking distance  (or two metro stops) from the Porta Nuova railway station, as well as from the Physics Department. No fee applies. For practical purposes, I kindly ask all the participants to register. As for talks, one can either apply on the above indico page or write directly to donato@to.infn.it