Exploring two component doublet dark matter

We propose a two-component dark matter (DM) scenario by extending the Standard Model with two additional <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>S</a:mi><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mn>2</a:mn><a:msub><a:mo stretchy="false">)</a:mo><a:mi>L</a:mi></a:msub></a:math> doublets, one scalar, and another fermion. To ensure the stability of the DM components, we impose a global <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msub><e:mi mathvariant="script">Z</e:mi><e:mn>2</e:mn></e:msub><e:mo>×</e:mo><e:msubsup><e:mi mathvariant="script">Z</e:mi><e:mn>2</e:mn><e:mo>′</e:mo></e:msubsup></e:math> symmetry. The lightest neutral states for both the scalar and fermion, which are non-trivially transformed under the extended symmetry, behave as stable two-component DM candidates. While single components are underabundant due to their gauge interactions, in a mass region between <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>m</i:mi><i:mi>W</i:mi></i:msub></i:math> and 525 GeV for the scalar and a mass below 1200 GeV for the fermion, and the fermion DM conflicts with direct detection limits over the whole parameter space, having two components helps to saturate relic density in the regions with under-abundance. Compliance with direct detection constraints leads to two options, either introducing dim-5 effective operators, or embedding the scenarios into a complete UV theory, which reproduces a type II seesaw model, thus naturally including neutrino masses. We analyze the consequences of this scenario at the LHC.