Comments on the high-Q(2) HERA anomaly

Taking the reported high-Q(2) anomaly at HERA as a signal of new physics, we show that several independent considerations point towards s-channel leptoquark production as the most attractive interpretation, We argue that even this option is highly constrained by flavor-changing processes: the couplings must be accurately diagonal in the quark and lepton mass eigenstate basis and should preserve individual quark and lepton family numbers. We propose a dynamical mechanism that might produce this pattern; it has distinctive experimental consequences. (C) 1997 Elsevier Science B.V.