ECFA-Summary: Higgs, gamma-gamma and e-gamma physics

Recent results obtained within ECFA/DESY and ECFA Study by the Higgs and gamma gamma /e gamma physics working groups are presented.Comment: Talk at EPS2003, 3 pages, 15 eps figures, svepj.clo and svjour.cl

Photon and its hadronic interaction

A short overview of basics aspects of hadronic interaction of the photon is presented.Comment: Introduction to PHOTON2003, 2 pages, 2 ps figures, espcrc2.sty, to appear in Proceeding

Photoproduction of isolated photons at HERA in NLO QCD

The NLO QCD calculation for the photoproduction of the isolated photon with a large $p_T$ at the HERA $ep$ collider is presented. The single resolved photon contribution and the QCD corrections of order $\alpha_s$ to the Born term are consistently included. The sizeable NNLO contributions, the box and the double resolved photon subprocesses, are taken into account in addition. The importance of the isolation cut, as well as the influence of other experimental cuts on the p_T and rapidity eta_gamma distributions are discussed in detail. Results are compared with experimental data and with the different NLO calculations.Comment: Latex(iopams style files included),14 pages,17 ps and 4 eps figures, talk at Ringberg Workshop: New Trends in HERA Physics 2001 and at Workshop on Small x Physics, Cracow, June 200