Doubly-charged scalars, predicted in many models having exotic Higgs representations, can in general have lepton-number violating (LFV) couplings. We show that by using an associated monoenergetic final state photon seen at a future linear $e^{-} e^{-}$ collider, we can have a clear and distinct signature for a doubly-charged resonance. The strength of the $\Delta L = 2$ coupling can also be probed quite effectively as a function of the recoil mass of the doubly-charged scalar.

Loop-driven decay modes of the Higgs are sensitive to new physics contributions because of new particles in the loops. To highlight this we look at the dilepton-dijet signal in the dominant Higgs production channel at a linear $e^{+} e^{-}$ collider. We show that by taking a simple ratio between cross-sections of two different final states such contributions can be very easily identified.