Cosmic rays: new insights in the precision era
Yoann Génolini, LAPTH Annecy
Recent experiments (notably PAMELA and, more recently, AMS-02) are ushering us into a new era of measurements of cosmic-ray fluxes with greatly reduced statistical uncertainties. These high precision measurements offer new opportunities for a number of astroparticle problems, such as indirect dark matter searches. In particular, astrophysical anti-particle fluxes are thought to be produced only by collisions of cosmic rays on the interstellar medium, and their relatively low flux makes them a channel of choice to look for rare processes. Nonetheless, the prediction of these expected backgrounds relies on a precise modeling of the cosmic ray propagation and interaction in the Galaxy, usually constrained by « secondary over primary » ratios. I will show that the predictions for the most widely used among these probes, the boron-to-carbon ratio (B/C), strongly depends on underlying assumptions. Under some simplified hypotheses on the propagation scenario, I will present two of our studies reevaluating anti-protons and positrons fluxes in the light of new AMS02 data, and discuss the implications for dark matter. (continued below)
(The slides will be available here)
(cont.) The extreme precision of the current data also challenges the degree of realism of the source term in modeling primary cosmic ray species. For instance, a continuum limit for the space-time distribution of sources is often assumed. I will outline our newly developed probabilistic theory to deal with a more realistic source term, accounting for the space-time discreteness of the cosmic ray injection, and discuss a few applications regarding the proton flux.