Sneutrino Factory

We argue that future e^{+} e^{-} linear colliders can produce many sneutrinos if lepton-number violating couplings lambda_{1j1} exist and enough beam polarization is obtained. The terms lambda_{ijk} L_{i} L_{j} E_{k}^{c} are allowed in a discrete Z_{3}-symmetry which is used to forbid rapid proton decay, and it is worthwhile to consider the possibility of the existence of such terms and their resultant. We study the process e^{+}e^{-} -> sneutrino -> e^{+} e^{-} in detail, and show that if such resonance is not found, lepton-number violating couplings lambda_{1j1}, will be strongly constrained. If we assume sneutrino mass m_{sneutrino}=500 GeV, beam polarization P_{e^{-}}=0.9, P_{e^{+}}=0.6, and integrated luminosity L=100 fb^{-1}, non-observation of sneutrino resonance will lead to lambda_{1j1} < 0.02 (if all charginos, and neutralinos, are lighter than the sneutrino), or lambda_{1j1} < 0.003 (if all charginos, and neutrainos, are heavier than the sneutrino).