Single sparticle and leptoquark production in $e^{+}e^{-}$ collisions up to $\sqrt{s}$=202 GeV with the DELPHI detector

Searches for single sparticle productions occurring in R-violating supersymmetry, have been performed, using the data collected by the DELPHI detector at LEP up to square root s=202 GeV. In particular, the resonant sneutrino production and subsequent decay to a single chargino or neutralino are studied, and limits on the associated R- parity violating couplings, at 95% CL, are presented. Relevant aspects on the R-violating squark and on a scalar leptoquark single production are given. A direct search for the single production of scalar and vector leptoquarks has been performed and limits are derived on the masses and couplings of the leptoquark states within two different frameworks, based on the direct (perturbative) and the resolved photon contribution. (5 refs).