Martin Wessels

General search for new phenomena in ep scattering at HERA

A model-independent search for deviations from the Standard Model prediction has been performed in e+p and e–p collisions at HERA using H1 data. All experimentally measurable event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta have been investigated. A good agreement with the Standard Model prediction is found in most of the event classes. A new algorithm has been developed to look for regions with large deviations from the Standard Model in the invariant mass and sum of transverse momenta distributions and to quantify the significance of the fluctuations observed. The largest deviation is found in topologies with an isolated muon, missing transverse momentum and a jet which confirms previous observations. About 2% of hypothetical Monte Carlo experiments would produce deviations more significant than the one observed in the corresponding distribution of sum of transverse momenta.