BOUNDS ON QCD INSTANTONS FROM HERA

Signals for processes induced by QCD instantons pre searched for in HE RA data on the hadronic final state in deep-inelastic scattering. The maximally allowed fraction of instanton-induced events is found at 95% confidence level to be on the percent level in the kinematic domain 1 0(-4) less than or similar to x less than or similar to 10(-2) and 5 l ess than or similar to Q(2) less than or similar to 100 GeV2. The most stringent limits are obtained from the multiplicity distributions. (C ) 1998 Elsevier Science B.V.