Measurement of leading neutron production in deep-inelastic scattering at HERA

The production of leading neutrons, where the neutron carries a large fraction xL of the incoming proton’s longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb−1. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6structure function, \(F_{2}^{LN(3)}(Q^{2},x,x_{L})\), and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of Q2, x and xL. Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function.