R-PARITY VIOLATION AT HERA

We summarize the signals at HERA in supersymmetric models with explicitly broken R-parity. As the most promising case, we consider in detail the resonant production of single squarks through an operator L(l)Q(i)D(j)BAR, a production process analogous to that for leptoquarks. However, the dominant decay of the squark to a quark and a photino leads to a very different experimental signature. We examine in particular the case where the photino decays to a positron and two quarks. Using a detailed Monte Carlo procedure we obtain a discovery limit in the squark mass-Yukawa coupling plane. HERA can discover a squark for a mass as large as 270 GeV and for an R-parity violating Yukawa coupling as small as 5.8 x 10(-3).