Forward Observables at RHIC, the Tevatron Run II and the LHC

Abstract

We present predictions on the total cross sections and on the ratio of the real part to the imaginary part of the elastic amplitude (ρ parameter) for present and future pp andpp colliders, and on total cross sections for γp → hadrons at cosmic-ray energies and for γγ → hadrons up to √ s = 1 TeV. These predictions are based on a study of many possible analytic parametrisations and invoke the current hadronic dataset at t = 0. The uncertainties on total cross sections, including the systematic theoretical errors, reach 1% at RHIC, 3% at the Tevatron, and 10% at the LHC, whereas those on the ρ parameter are respectively 10%, 17%, and 26%.This report is based on ref.[1], which constitutes the conclusion of an exhaustive study [2] of analytic parametrisations of soft forward data at t = 0. As explained in V. V. Ezhela's contribution to these proceedings, this study has three main purposes. First of all, it helps maintain the dataset of cross sections and ρ parameters available to the community. Secondly, it enables us to decide which models are the best, and in which region of s. Finally, and this will be the main object of this report, it enables us to make predictions based on a multitude of models, and on all available data.

A complete 3D numerical study of the effects of pseudoscalar–photon mixing on quasar polarizations

“…In this section we give the basic equations of pseudoscalar-photon mixing in an expanding universe [87][88][89]. We assume the standard Friedmann-Robertson-Walker (FRW) metric, with the curvature parameter k = 0, using conformal time.…”

Forward elastic scattering and Pomeron models

“…Eqs. (4) and (5) bring enclosed analytic structures similar to those appearing in some well known models, as for example, Donnachie and Landshoff (DL) [8], Block and Halzen (BH) [30], COMPETE and PDG parameterizations (COMPETE) [10][11][12]. We shall consider four particular cases, distinguished by the corresponding Pomeron contributions (σ P ), defined and denoted as follows.…”

“…Historically, the leading contribution to σ tot at the highest energies has been associated with an even-under-crossing object named Pomeron (from a QCD viewpoint, a color singlet made up of two gluons in the simplest configuration) [6]. Typical Pomeron models consider contributions associated with either a simple pole at J = α 0 (for example, Donnachie and Landshoff [8] and some QCD-inspired models [9]) or a triple pole at J = 1 (as selected in the detailed analysis by the COMPETE Collaboration [10,11] and used in the successive editions of the Review of Particle Physics, by the Particle Data Group (PDG) [12]).…”

Soft diffraction within the QCD color dipole picture

“…where A = 29.6 ± 1.2 mb, D = 0.251 ± 0.010 mb and s 0 = 4m 2 p 3.521 GeV 2 . As this model is inspired in the COMPETE analysis (pre-LHC) [61][62][63] we shall refer to it as "Broilo-Luna-Menon (BLM)" model.…”