Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

Inelastic photoproduction of J/Psi mesons at HERA

An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 6

Measurement of inclusive jet cross sections in photoproduction at HERA

Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of e+p→e++jet+X events in the kinematic range of photon virtualities Q2≤1GeV2 and photon-proton centre-of-mass energies 95≤Wγp≤285GeV represents an integrated luminosity of 24.1pb−1. Jets are defined using the inclusive k⊥ algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy E T jet and pseudorapidity ηjet in the domain 5≤EjetT≤75GeV and −1≤ηjet≤2.5. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in E T jet , which varies by six orders of magnitude over the measured range, is compared with similar distributions from pp¯¯¯ colliders at equal and higher energies.ISSN:1434-6044ISSN:1434-605