Singlet-doublet fermionic dark matter, neutrino mass, and collider signatures

We propose a minimal extension of the standard model by including a scalar triplet with hypercharge 2 and two vectorlike leptons, one doublet and a singlet, to explain simultaneously the nonzero neutrino mass and dark matter (DM) content of the Universe. The DM emerges as a mixture of the neutral component of the vectorlike lepton doublet and singlet, being odd under a discrete Z₂ symmetry. After electroweak symmetry breaking the triplet scalar gets an induced vacuum expectation value, which gives Majorana masses not only to the light neutrinos but also to the DM. Because of the Majorana mass of DM, the Z mediated elastic scattering with nucleon is forbidden. However, the Higgs boson mediated direct detection cross section of the DM gives an excellent opportunity to probe it at Xenon1T. The DM cannot be detected at the collider. However, the charged partner of the DM (often next-to-lightest stable particle) can give large displaced vertex signature at the Large Hadron Collider.