RECENT RESULTS FROM EP INTERACTIONS AT HERA

Abstract

AbstractIn this writeup a selection of recent results from the experiments H1 and ZEUSwith electron-proton collisions at HERA is presented. After a brief introduction, thereview covers structure functions, QCD fits and the determination of α s , heavy fla-vor production, determination of electroweak parameters, spectroscopy and search fornew physics. The results described use mostly the full HERA I luminosity but firstmeasurements from HERA II data using collisions with polarised e ± beam are alsopresented. Prospects for future measurements with HERA II and their relevance forfuture high energy physics experiments are addressed. 1 Introduction HERA is the first and only high energy electron-proton collider. After being commisioned in1992, during the years 1994-2000 the accelerator delivered a total of about 120 pb −1 to eachof the two colliding experiments, H1 and ZEUS. The HERA II upgrade, started in 2001 andfinalized in year 2003, aiming at an increase of the luminosity and at the use of a polarisedelectron beam, will provide by mid of 2007 a fivefold increase of the total luminosity.Collisions at HERA of 27.5 GeV electrons (or positrons) with 920 GeV protons, corre-sponding to a center-of-mass energy of 319 GeV, are equivalent to a fixed target experimentwith a 54 TeV electron beam. At the lowest order the scattering process is described by thee