Amount of Antiprotons in Cosmic Rays due to Halo Neutralino Annihilation

We evaluate the antiproton–to–proton flux ratio which can be generated by neutralino–neutralino annihilation in the galactic halo, considering the most general compositions for the relic neutralinos and modelling the neutralino local density according to its relic abundance. We find that in the case of mixed neutralino compositions this ¯ p/p ratio is higher than for pure higgsinos or gauginos. It is shown how the expected improvements in sensitivity for the new measurements of the ¯ p/p may provide very useful information, complementary to the one obtainable with other experimental means.