Novel Collider Signatures for Little Higgs Dark Matter Models

Abstract

Little Higgs models with $T$-parity provide a stable neutral particle $A_H$, the lightest $T$-odd particle (LTP), which was recently proposed to explain the cold dark matter of the Universe. In the coannihilation region of the LTP with the Little Higgs partner of the light quark $Q_H$, we propose novel signatures for its detection at hadronic colliders by searching for monojet and dijet plus missing energy events due to the associated production of $Q_H A_H$ and direct production of $Q_H \bar{Q}_H$, respectively. Using the most recent WMAP data, we show that the coupling of $A_H$-$Q_H$-$q$ is tightly constrained in the coannihilation region. This implies that the monojet signal is too small to be discernible but the dijet plus missing energy signal is potentially measurable at the LHC.