Model-independent implications of the e+, e-, anti-proton cosmic ray spectra on properties of Dark Matter

TL;DR

This paper classifies dark matter annihilation channels and analyzes cosmic ray data to infer properties of dark matter particles, suggesting either very heavy particles or leptophilic annihilation as explanations for observed positron excesses.

Contribution

It provides a model-independent classification of dark matter annihilation channels considering polarization states and connects cosmic ray data to dark matter properties, highlighting two possible scenarios.

Findings

Dark matter particles annihilating into W,Z,h must be heavier than 10 TeV or annihilate only into leptons.

A peak around 700 GeV in the e++e- spectrum suggests TeV-scale leptophilic dark matter.

Results have implications for dark matter models, detection, and collider searches.

Abstract

Taking into account spins, we classify all two-body non-relativistic Dark Matter annihilation channels to the allowed polarization states of Standard Model particles, computing the energy spectra of the stable final-state particles relevant for indirect DM detection. We study the DM masses, annihilation channels and cross sections that can reproduce the PAMELA indications of an e+ excess consistently with the PAMELA p-bar data and the ATIC/PPB-BETS e++e- data. From the PAMELA data alone, two solutions emerge: (i) either the DM particles that annihilate into W,Z,h must be heavier than about 10 TeV or (ii) the DM must annihilate only into leptons. Thus in both cases a DM particle compatible with the PAMELA excess seems to have quite unexpected properties. The solution (ii) implies a peak in the e++e- energy spectrum, which, indeed, seems to appear in the ATIC/PPB-BETS data around 700 GeV. If upcoming data from ATIC-4 and GLAST confirm this feature, this would point to a O(1) TeV DM annihilating only into leptons. Otherwise the solution (i) would be favored. We comment on the implications of these results for DM models, direct DM detection and colliders as well as on the possibility of an astrophysical origin of the excess.