Jets and Energy Flow in Photon-Proton Collisions at HERA

: Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to pp data and QCD calculations. The comparisons show that the flp events can be consistently described by QCD models including -- in addition to the primary hard scattering process -- interactions between the two beam remnants. The differential jet cross sections doe=dE jet T and doe=dj jet are measured. H1 Collaboration S. Aid 14 , V. Andreev 26 , B. Andrieu 29 , R.-D. Appuhn 12 , M. Arpagaus 37 , A. Babaev 25 , J. Bahr 36 , J. B'an 18 , Y. Ban 28 , P. Baranov 26 , E. Barrelet 30 , R. Barschke 12 , W. Bartel 12 , M. Barth 5 , U. Bassler 30 , H.P. Beck 38 , H.-J. Behrend 12 , A. Belousov 26 , Ch. Berger 1 , G. Bernardi 30 , R. Bernet 37 , G. Bertrand-Coremans 5 , M. Besan¸con 10 , R. Beyer 12 , P. Biddulp..