Leading neutron production in deep inelastic scattering at HERA

Events with a high energy neutron produced at small angles with respect to the proton beam direction have been observed by the H1 experiment at HERA. The observed energy and \t\ distributions of final-state neutrons with energy E-n greater than or equal to 400 GeV are in good agreement with the predictions of Monte Carlo models based on pion exchange, and with those based on string fragmentation. In the kinematic range 5 less than or equal to Q(2) less than or equal to 100 GeV2 and 0.05 less than or equal to y less than or equal to 0.7, the fraction of e - p collisions which contain a neutron with E-n greater than or equal to 400 GeV and \t\ < 0.5 GeV2 is (7.8(-2.0)(+3.0))%. The fraction of DIS events which contain a neutron with E-n greater than or equal to 100 GeV is independent of Q(2) and x(BJ), and is consistent with having the same multiplicity distribution as does the fully inclusive DIS sample.