What if charged current events at large Q2 are observed at HERA? Original Research Article

An excess of events at large Q2 with a positron in the final state has been observed at HERA which, if confirmed, could be a signal of new physics. It is not clear at present if a signal of comparable rate is also seen in the charged-current channel (with an antineutrino in the final state). In this note we analyse the implications of the presence of such a signal in models of new physics based on contact terms, leptoquarks and squarks with R-violating decays. We find that in all cases the most likely possibility is that the charged-current signal is absent. As a consequence, if this signal is present the resulting indications are very selective. In particular for squarks only charged-current events with multi-quark final states are possible with quite definite predictions on the spectrum of supersymmetric particles.