Cross section of isolated prompt photons in hadron-hadron collisions

We consider the production of isolated prompt photons in hadronic collisions. We present a general discussion in QCD perturbation theory of the isolation criterion used by hadron collider experiments. The isolation criterion is implemented in a computer programme of the Monte Carlo type, which evaluates the production cross section at next-to-leading order accuracy in perturbative QCD. The calculation includes both the direct and the fragmentation components of the cross section, without any approximation of the dependence on the radius R of the isolation cone. We examine the scale dependence of the isolated cross section, the sensitivity of the cross section to the values of the isolation parameters, and we provide a quantitative comparison between the full R dependence and its small-R approximation.Comment: 29 pages, 1 figure, few comments slightly expanded, results unchanged, misprints correcte

Large Transverse Momenta in Statistical Models of High Energy Interactions

The creation of particles with large transverse momenta in high energy hadronic collisions is a long standing problem. The transition from small- (soft) to hard- parton scattering `high-pt' events is rather smooth. In this paper we apply the non-extensive statistical framework to calculate transverse momentum distributions of long lived hadrons created at energies from low (sqrt(s)~10 GeV) to the highest energies available in collider experiments (sqrt(s)~2000 GeV). Satisfactory agreement with the experimental data is achieved. The systematic increase of the non-extensivity parameter with energy found can be understood as phenomenological evidence for the increased role of long range correlations in the hadronization process. Predictions concerning the rise of average transverse momenta up to the highest cosmic ray energies are also given and discussed.Comment: 20 pages, 10 figure

Electroweak Physics at LHC

The prospects for electroweak physics at the LHC are reviewed focusing mainly on precision studies. This includes projections for measurements of the effective Z pole weak mixing angle, of top quark, W boson, and Higgs scalar properties, and new physics searches

Re-evaluation of the LHC potential for the measurement of Mw

We present a study of the LHC sensitivity to the W boson mass based on simulation studies. We find that both experimental and phenomenological sources of systematic uncertainties can be strongly constrained with Z measurements: the lineshape is robustly predicted, and its analysis provides an accurate measurement of the detector resolution and absolute scale, while the differential cross-section analysis absorbs most of the strong interaction uncertainties. A sensitivity \delta Mw \sim 7 \MeV for each decay channel (W --> e nu, W --> mu nu), and for an integrated luminosity of 10 fb-1, appears as a reasonable goal