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The lepton–proton collisions produced at the HERA collider represent a unique high energy physics data set. A number of years after the end of collisions, the data collected by the H1 experiment, as well as the simulated events and all software needed for reconstruction, simulation and data analysis, were migrated into a preserved operational mode at DESY. A recent modernisation of the H1 software architecture has been performed, which will not only facilitate on going and future data analysis efforts with the new inclusion of modern analysis tools, but also ensure the long-term availability of the H1 data and associated software. The present status of the H1 software stack, the data, simulations and the currently supported computing platforms for data analysis activities are discussed.

The first measurement of exclusive photoproduction of ρ 0 mesons associated with leading neutrons at HERA is presented. The data are taken with the H1 detector in the years 2006-2007 at √ s = 319 GeV and correspond to an integrated luminosity of 1.16 pb −1 . ρ 0 mesons are reconstructed from their decays to pions in the central tracking chamber, while leading neutrons carrying a large fraction of the incoming proton momentum, x L > 0.35, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality Q 2 < 2 GeV 2 , the total energy of the photon-proton system 20 < W γp < 100 GeV and the polar angle of the leading neutron, θ n < 0.75 mrad. The cross section of the reaction γ p → ρ 0 nY , where Y is a small mass system escaping undetected in the proton direction, is measured as a function of the neutron energy, of the effective mass of the π + π − system as well as of the transverse momentum squared, p 2 t , and of the pseudorapidity η of ρ meson. The data are interpreted in terms of the double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ρ meson on the virtual pion. In the framework of OPE approach elastic cross section of photon-pion scattering, σ el (γπ + → ρ 0 π + ) at average energy W γπ = 22 GeV is extracted.