New scalar resonances from sneutrino-Higgs mixing in supersymmetry with small lepton number (R-parity) violation

We consider new s-channel scalar exchanges in top quark and massive gauge-bosons pair production in e+e- collisions, in supersymmetry with a small lepton number violation. We show that a soft bilinear lepton number violating term in the scalar potential which mixes the Higgs and the slepton fields can give rise to a significant scalar resonance enhancement in e+e- -> ZZ, W+W- and in e+e- -> t t(bar). The sneutrino-Higgs mixed state couples to the incoming light leptons through its sneutrino component and to either the top quark or the massive gauge bosons through its Higgs component. Such a scalar resonance in these specific production channels cannot result from trilinear Yukawa-like R-parity violation alone, and may, therefore, stand as strong evidence for the existence of R-parity violating bilinears in the supersymmetric scalar potential. We use the LEP2 measurements of the WW and ZZ cross-sections to place useful constrains on this scenario, and investigate the expectations for the sensitivity of a future linear collider to these signals. We find that signals of these scalar resonances, in particular in top-pair production, are well within the reach of linear colliders in the small lepton number violation scenario.