Top Quark Mediated Dark Matter

TL;DR

This paper investigates dark matter interactions mediated by the top quark, highlighting loop-induced photon and gluon couplings, and discusses implications for gamma ray searches and collider experiments.

Contribution

It introduces a model where dark matter interacts via the top quark portal with suppressed tree-level annihilation, emphasizing loop-induced photon and gluon channels.

Findings

Photon channel has a substantial rate when main annihilation is into gluons.

LHC data constrains the photonic annihilation cross section to ~10^{-28} cm^3/s.

The model is compatible with a thermal WIMP scenario.

Abstract

We study the top quark portal dominated dark matter interactions, and its implications for the gamma ray line searches. In this picture, the dark matter interactions with photons and gluons are loop induced by the axial anomaly of the top quark current. We show there can be a natural suppression of the tree-level annihilation of dark matter, and the photon channel in turn has a substantial rate when the main annihilation proceeds into gluons. We observe a competition between the indirect detection of gamma ray line and the search with monojet plus missing energy events at LHC, and the 7 TeV data already set an upper bound of ~ 10^{-28} cm^3/s on the photonic annihilation cross section. This upper limit is compatible with a thermal WIMP scenario.