Searching for Elko dark matter spinors at the CERN LHC

Abstract

The aim of this work is to explore the possibility to discover a fermionic field with mass dimension one, the Elko field, in the Large Hadron Collider (LHC). Due to its mass dimension, an Elko can only interact either with Standard Model (SM) spinors and gauge fields at 1-loop order or at tree level through a quartic interaction with the Higgs field. In this Higgs portal scenario, the Elko is a viable candidate to a dark matter constituent which has been shown to be compatible with relic abundance measurements from WMAP and direct dark matter--nucleon searches. We propose a search strategy for this dark matter candidate in the channel $pp \rightarrow l^+ l^- + \not\!\! E_T$ at the $\sqrt{s}=14$ TeV LHC. We show the LHC potential to discover the Elko considering a triple Higgs-Elko coupling as small as $\sim 0.5$ after 1 pb$^{-1}$ of integrated luminosity. Some phenomenological consequences of this new particle and its collider signatures are also discussed.