Loop induced top quark FCNC through top quark and dark matter interactions

TL;DR

This paper investigates loop-induced flavor-changing neutral current signals involving the top quark and dark matter at the LHC, highlighting the interplay between collider and direct detection constraints within a simplified model.

Contribution

It introduces a simplified model with Majorana dark matter that predicts loop-induced top quark FCNC processes and analyzes their detectability at the LHC and in direct detection experiments.

Findings

Next-to-leading order corrections are significant for dark matter direct detection.

Collider and direct detection experiments together constrain the model parameters.

Spin-independent scattering vanishes at leading order, affecting detection prospects.

Abstract

We present a comprehensive analysis of the loop induced top quark FCNC signals at the LHC within one class of the simplified model. The loop level FCNC interactions are well motivated to avoid the hierarchy of the top quark couplings from the new physics and standard model. Such a theory will posit a Majorana dark matter candidate and could be tested through dark matter relic density, direct detection experiments (the scattering between dark matter and heavy nuclei), and the collider signals at the LHC. We find that the spin-independent (SI) scattering between Majorana dark matter and nuclei will vanish at the leading order, while the next-to-leading order correction to the SI scattering becomes significance to constrain the parameter space of the model. A detailed comparison from direct detection experiments and LHC searches is also discussed and both of them are very important to full constrain the model.