Abstract
Dark matter annihilation to leptons, , is necessarily accompanied by electroweak radiative corrections, in which a or boson is radiated from a final-state particle. Given that the and gauge bosons decay dominantly via hadronic channels, it is thus impossible to produce final-state leptons without accompanying protons, antiprotons, and gamma rays. Significantly, while many dark matter models feature a helicity-suppressed annihilation rate to fermions, radiating a massive gauge boson from a final-state fermion removes this helicity suppression, such that the branching ratios , , and dominate over . bremsstrahlung thus allows indirect detection of many weakly interacting massive particle models that would otherwise be helicity suppressed, or suppressed. Antiprotons and even antideuterons become consequential final-state particles. This is an important result for future dark matter searches. We discuss the implications of bremsstrahlung for “leptonic” dark matter models which aim to fit recent cosmic ray positron and antiproton data.
- Received 25 September 2010
DOI:https://doi.org/10.1103/PhysRevD.83.013001
© 2011 American Physical Society