Measurement of Feynman-$x$ Spectra of Photons and Neutrons in the Very Forward Direction in Deep-Inelastic Scattering at HERA

Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic \(ep\) scattering at HERA are presented as a function of the Feynman variable \(x_F\) and of the centre-of-mass energy of the virtual photon-proton system \(W\). The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of \(131~\text {pb}^{-1}\). The measurement is restricted to photons and neutrons in the pseudorapidity range \(\eta >7.9\) and covers the range of negative four momentum transfer squared at the positron vertex \(6deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.