A search for leptoquark bosons in e−pcollisions at HERA

A search for scalar and vector leptoquarks coupling to first generation fermions is performed in the H1 experiment at the epcollider HERA. The analysis uses e−pdata collected in 1998 and 1999 at a centre-of-mass energy of 320 GeV, corresponding to an integrated luminosity of ∼15 pb−1. No evidence for the direct production of such particles is found in a data sample with a large transverse momentum final state electron or with large missing transverse momentum, and constraints on leptoquark models are established. For a Yukawa coupling of electromagnetic strength leptoquarks are excluded for masses up to ∼290 GeV. This analysis complements the leptoquark searches performed previously using data collected whilst HERA was operating with positrons instead of electrons.