Testing radiative neutrino mass models at the LHC

The Large Hadron Collider provides us new opportunities to search for the origin of neutrino mass. Beyond the minimal see-saw models a plethora of models exist which realise neutrino mass at tree- or loop-level, and it is important to be sure that these possibilities are satisfactorily covered by searches. The purpose of this paper is to advance a systematic approach to this problem. Majorana neutrino mass models can be organised by SM-gauge-invariant operators which violate lepton number by two units. In this paper we write down the minimal ultraviolet completions for all of the mass-dimension 7 operators. We predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged scalar, a scalar doublet, and a scalar quadruplet, whose properties are constrained by neutrino oscillation data. A detailed collider study is presented for O-3 = LLQ (d) over barH and O-8 = L (d) over bar(e) over bar (dagger)(u) over bar (dagger) H completions with a vector-like quark chi similar to (3,2,-5/6) and a leptoquark phi similar to ((3) over bar ,1,1/3). The existing LHC limits extracted from searches for vector-like fermions and sbottoms/stops are m(chi) greater than or similar to 620 GeV and m(phi) greater than or similar to 600 GeV.