Piero Ullio — Page 4

arXiv1999

Cosmic antiprotons as a probe for neutralino dark matter?

The flux of cosmic ray antiprotons from neutralino annihilations in the galactic halo is computed for a large sample of models in the Minimal Supersymmetric extension of the Standard Model. We also revisit the problem of estimating the background of low-energy cosmic ray induced secondary antiprotons, taking into account their subsequent interactions (and energy loss) and the presence of nuclei in the interstellar matter. We point out that in some cases the optimal kinetic energy to search for a signal from supersymmetric dark matter is above several GeV, rather than the traditional sub-GeV region. The large astrophysical uncertainties involved do not allow the exclusion of any of the MSSM models we consider, on the basis of current data.

astro-ph↗

arXiv1999

Signatures of exotic physics in antiproton cosmic ray measurements

More than a decade ago it was noticed that an unexpectedly large value of the measured cosmic antiproton flux at low kinetic energies could be interpreted in terms of a neutralino-induced component. An overproduction of low energy antiprotons seems however to be disfavoured by recent data from the BESS experiment. The strategy we propose here is to focus instead on the high energy antiproton spectrum. We find cases in which the signal from neutralino annihilations in a clumpy halo scenario can be unambiguously distinguished from the cosmic ray induced component. Such signatures can be tested in the near future by upcoming experiments. We investigate also the possibility that antiprotons have a finite lifetime. We find cases in which the neutralino-induced flux is consistent with present data for a lifetime as low as 0.15 Myr, in clear violation of a recent bound derived from the antiproton cosmic ray flux.

astro-ph↗