A search for resonance decays to anti ν-jet in e+p scattering at HERA

A study of the anti ν-jet mass spectrum in e+p→ anti νX events at center-of-mass energy 300 GeV has been performed with the ZEUS detector at HERA using an integrated luminosity of 47.7 pb-1. The mass spectrum is in good agreement with that expected from standard model processes over the anti ν-jet mass range studied. No significant excess attributable to the decay of a narrow resonance is observed. By using both e+p→e+X and e+p→ anti νX data, mass-dependent limits are set on the s-channel production of scalar and vector resonant states. Couplings to first-generation quarks are considered and limits are presented as a function of the e+q and anti νq branching ratios. These limits are used to constrain the production of leptoquarks and R-parity violating squarks. (orig.)