Frascati resummation schemes for IR radiation in QED and QCD

As part of the 70th birthday celebration of our dear friend Mario Greco, a brief history of the development of radiative effects at Frascati in QED and QCD covering the period between late sixties to the late eighties is presented. During these two decades, two parallel resummation schemes for QED were formulated and radiative corrections were made for the J/Ψ production and later for Z0 production. The schemes were then extended to QCD to obtain realistic estimates of the e+e− hadronic cross-sections at all energies. It led to the introduction of several new concepts: frozen αs and later to singular αs and to the notion of the maximum value of transverse energy allowed in a radiative process. Some other fall outs from this research such as transverse momentum distributions and hadronic total crosssections which are valid even now would be briefly touched upon

Total Cross Sections

A unified approach to total cross-sections, based on the QCD contribution to the rise with energy, is presented for the processes $pp$, $p{\bar p}$, $\gamma p, \gamma \gamma, e^+e^- \to hadrons$. For proton processes, a discussion of the role played by soft gluon summation in taming the fast rise due to mini-jets is presented. For photon-photon processes, a comparison with other models indicates the need for precision measurements in both the low and high energy region, likely only with measurements at future Linear Colliders.Comment: 15 pages, 9 figures, LaTeX, uses hsproc.sty and art10.sty. Talk given by G. Pancheri at 'International Hadron Structure-2000', October 1-6, Staralesn

Total Cross-sections and Bloch-Nordsieck Gluon Resummation

The physics underlying the fall and eventual rise in various total cross-sections at high energies has been investigated over a decade using a model based on the Bloch-Nordsieck resummation in QCD. Here a brief review of our latest results is presented and comparison made with experimental data on $pp$, $\gamma proton$ and $\gamma \gamma$ total cross-sections.Comment: Presented by G. Pancheri at ISMD04, Sonoma State University. Under publication in Acta Physica Polonica. LaTeX format, 10 *.eps files, 7 page

Total cross sections and soft gluon resummation

We discuss a model for total hadronic and photonic cross-sections which includes hard parton-parton scattering to drive the rise and soft gluon resummation to tame it. Unitarity is ensured by embedding the cross-section in the eikonal formalism. Predictions for LHC and ILC are presented.Comment: 9 pages, 2 figures, Presented at PLC2005, Kazimierz, September 2005, requires appolb.cl

Soft Gluons and the Energy Dependence of Total Cross-Sections

We discuss the high energy behaviour of total cross-sections for protons and photons, in a QCD based framework with particular emphasis on the role played by soft gluonsComment: 13 pages, 10 figures, Presented by G. Pancheri at the International Workshop on QCD, Martina Franca, Italy, June 16-20,2001. To appear in the proceeding

Total Cross-sections at very high energies: from protons to photons

A model for both proton and photon total cross-sections is presented and compared with data. The model is based on the eikonal representation, with QCD mini-jets to drive the rise and soft gluon kt-resummation into the Infrared region to tame the excessive rise due to low-x perturbative gluons. We discuss the effects of a singular but integrable expression for the Infrared gluon spectrum on the high energy behaviour of the total cross-section expected in this model.Comment: 13 pages, 4 figures, Tenth Workshop on Non-Perturbative Quantum Chromodynamics at l'Institut Astrophysique de Paris, June 8-12, 200

Total cross-section at LHC from minijets and soft gluon resummation in the infrared region

A model for total cross-sections incorporating QCD jet cross-sections and soft gluon resummation is described and compared with present data on $pp$ and ${\bar p}p$ cross-sections. Predictions for LHC are presented for different parameter sets. It is shown that they differ according to the small x-behaviour of available parton density functions.Comment: 10 pages, 3 figures, uses appolb.cls, LaTeX. Talk presented by G. Pancheri at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz, Polan