Secondary antiprotons as a Galactic Dark Matter probe

TL;DR

This paper assesses the uncertainties in secondary antiproton flux predictions from cosmic-ray interactions, constrains dark matter models, and evaluates recent experimental data, finding no significant anomalies and supporting certain dark matter interpretations.

Contribution

It introduces a new method to determine astrophysical uncertainties in antiproton fluxes and provides conservative bounds on dark matter annihilation channels using recent cosmic-ray data.

Findings

Astrophysical uncertainties in antiproton fluxes are quantified.

Current antiproton data do not rule out dark matter explanations for gamma-ray excess.

Recent AMS-02 data are compatible with the proposed propagation models.

Abstract

We present a novel determination of the astrophysical uncertainties associated to the secondary antiproton flux originating from cosmic-ray spallation on the interstellar gas. We select a set of propagation models compatible with the recent B/C data from PAMELA, and find those providing minimal and maximal antiproton fluxes in different energy ranges. We use this result to determine the most conservative bounds on relevant Dark Matter (DM) annihilation channels: We find that the recent claim of a DM interpretation of a gamma-ray excess in the Galactic Center region cannot be ruled out by current antiproton data. Finally, we discuss the impact of the recently released preliminary data from AMS-02. In particular, we provide a reference model compatible with proton, helium and B/C spectra from this experiment. Remarkably, the main propagation parameters of this model are in agreement with the best fit presented in our earlier statistical analyses. We also show that the antiproton-to-proton ratio does not exhibit any significant anomaly at high energy with respect to our predictions.