Search for leptoquarks and contact interactions at HERA

A search for physics beyond the Standard Model is performed using high-Q 2 deep inelastic e ± p scattering data, corresponding to a total integrated luminosity of about 0.5 fb −1 per experiment, collected with the H1 and ZEUS detectors at HERA. ZEUS derives limits on the effective mass scale in eeqq contact interactions, on the ratio of the mass to the Yukawa coupling for heavy-leptoquark models, on the effective Planck-mass scale in models with large extra dimensions and on the quark charge radius. H1 searches for scalar and vector leptoquarks coupling to first and second generation fermions, and sets constraints on leptoquark models.