Constraints on neutrino parameters and doubly-charged Higgs particles in e−e− → W−W−

Doubly charged Higgs s-channel resonances are analyzed in the e−e− → W−W− process. In our analysis a recent stringent constraint on an effective neutrino mass 〈mv〉 coming from neutrinoless double-β decay is implemented. It is shown that due to a very restrictive limit on 〈mv〉 the doubly charged Higgs resonance predicted by the Standard Model with additional Higgs triplets is below the detection limit. For the same reason also the ΔL−− resonance cannot be visible in the framework of the conventional Left-Right symmetric model. The situation is quite different for the ΔR−− pole and large signal is possible here. Contributions of the s, t and u channels to the cross section around the ΔR−− peak are also discussed.