Search for single leptoquark production in e + e collisions up to p s =208 GeV with the DELPHI detector

A search for single production of scalar and vector leptoquarks of the rst generation have been performed using the data collected by the DELPHI detector at LEP. Limits at 95% condence level on the Yukawa couplings and masses of the leptoquark states were derived from the analysis of the data accumulated in the centre-of-mass energy region of 189 GeV up to 208 GeV with a total integrated luminosity of 539 pb 1 .