Soft Photoproduction Physics

Several topics of interest in soft photoproduction physics are discussed. These include jet universality issues (particle flavour composition), the subdivision into event classes, the buildup of the total photoproduction cross section and the effects of multiple interactions.Comment: 10 pages, LaTeX2e, no figures, to appear in the proceedings of the Durham Workshop on HERA Physics, ``Proton, Photon and Pomeron Structure'', 17--23 September 1995, Durham, U.

Working Group Report on the Structure of the Proton

We summarize the developments on the structure of the proton that were studied at the Workshop on "HERA Physics" that was held in Durham in September 1995. We survey the latest structure function data; we overview the QCD interpretations of the measurements of the structure functions and of final state processes; we discuss charm production and the spin properties of the proton.Comment: 45 pages, latex file using epsfig and ioplppt macros. Figures included, but full resolution figure files and postscript file of the whole paper are available via anonymous ftp at ftp://cpt1.dur.ac.uk/pub/preprints/dtp96/dtp962

Diffractive production of #rho#"0(770) mesons in muon-proton interactions at 470 GeV

The diffractive production of #rho#"0(770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV"2 < Q"3 < 20 GeV"2 and 20 GeV < #nu# < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q"2, x and #nu# dependence of the cross section, on the shape of the #pi#"+#pi#"- mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the #rho#"0(770). The cross section for diffractive production of #rho#"0 by virtual photons on protons depends mainly on Q"2. At fixed Q"2, no significant dependence on x or #nu# is observed. The extrapolation to Q"2 = 0 yields a photoproduction cross section of (10.30 #+-# 0.33) #mu#b. The slope of the t' distribution has a value of (7.0#+-#0.2) GeV"-"2, with a tendency to decrease as Q"2 increases. The production and decay angular distributions of the #rho#"0 depend strongly on Q"2 and are consistent with s-channel helicity conservation. The ratio R #sigma#_L/#sigma#_T deduced from the decay angular distributions rises strongly with Q"2, passing the value of 1 at Q"2 #approx# 2 GeV"2. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Production of charged hadrons by positive muons on deuterium and xenon at 490 GeV

Results on the production of charged hadrons in muon-deuteron and muon-xenon interactions are presented. The data were taken with the E665 spectrometer, which was exposed to the 490 GeV muon beam of the Tevatron at Fermilab. The use of a streamer chamber as vertex detector provides nearly 4#pi# acceptance for charged particles. The #mu#D data are compared with the #mu#Xe data in terms of multiplicity distributions, average multiplicities, forward-backward multiplicity correlations, rapidity and transverse momentum distributions and of two-particle rapidity correlations of charged hadrons. The data cover a range of invariant hadronic masses W from 8 to 30 GeV. (orig.)Available from TIB Hannover: RR 2916(93-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman