Proceedings of the 34th International Conference in High Energy Physics (ICHEP08), Philadelphia, PA, 2008, eConf C080730, [hep-ph/0809.xxx]

In 2004 a team from the University of Pennsylvania, Princeton University, and the Institute for Advanced Study proposed to host the 2008 International Conference on High Energy Physics (ICHEP) on the campus of the University of Pennsylvania in Philadelphia. The proposal was approved later that year by the C-11 committee of the International Union of Pure and Applied Physics. The Co-Chairs were Nigel S. Lockyer (U. Penn/TRIUMF) and A.J. Stewart Smith (Princeton); Joe Kroll of U. Penn served as Deputy Chair from 2007 on. Highlights of the proposal included 1. greatly increased participation of young scientists, women scientists, and graduate students 2. new emphasis on formal theory 3. increased focus on astrophysics and cosmology 4. large informal poster session (170 posters) in prime time 5. convenient, contiguous venues for all sessions and lodging 6. landmark locations for the reception and banquet. The conference program consisted of three days of parallel sessions and three days of plenary talks

Measurement of charged-particle multiplicities in gluon and quark jets in p(p)over-bar collisions at root s=1.8 TeV

We report the first largely model independent measurement of charged particle multiplicities in quark and gluon jets, N-q and N-g, produced at the Fermilab Tevatron in p (p) over bar collisions with a center-of-mass energy of 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies of 41 and 53 GeV by counting charged particle tracks in cones with opening angles of θ(c)=0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q=E-jetθ(c) varies in the range from 12 to 25 GeV. At Q=19.2 GeV, the ratio of multiplicities r=N-g/N-q is found to be 1.64± 0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with resummed perturbative QCD calculations