Search for resonant ν̃ production at √s = 183 to 208 GeV: The DELPHI collaboration

Searches for resonant ν production in e+e- collisions under the assumption that R-parityis not conserved and that the dominant R-parityviolating coupling is λ121m or λ131 used data recorded by DELPHIin 1997 to 2000 at centre-of-mass energies of 183 to 208 GeV. No deviation from the Standard Model was observed. Upper limits are given for the λ121 and λ131 couplings as a function of the sneutrino mass and total width. The limits are especially stringent for sneutrino masses equal to the centre-of-mass energies with the highest integrated luminosities recorded.