Mass determination of invisibly decaying sneutrinos at the ILC

For points in SUSY parameter space where the sneutrino is the NLSP, direct mass determination from pair production is impossible since they decay invisibly. For such a scenario, we investigate the precision of the sneutrino mass determination by the means of three particle decays in chargino pair production at the ILC. The SM and SUSY backgrounds are included in our study using full matrix elements from the event generator WHIZARD, as well as smearing effects from ISR and beamstrahlung. Especially, off-shell intermediate states lead to a shift in the mass edge distributions from which the sneutrino and chargino mass are determined