No Arabic abstract
In this paper we present a two channel model with the goal of reproducing the soft scattering data available in the ISR-Tevatron energy range, and extend the model results to LHC and Cosmic Rays energies. A characteristic feature of the model is that we represent the sum of all diffractive final states at a vertex, by a single diffractive state. Our two main results are: (i) The approach of the elastic scattering amplitude to the black disc bound is very slow, reaching it at energies far higher than the GZK ankle cutoff. (ii) Our predicted survival probability for Higgs exclusive central diffractive production at the LHC is 0.7%, which is considerably smaller than our previous estimate. The above features are compatible with a parton-like model in which the traditional soft Pomeron is replaced by an amplitude describing the partonic system, which issaturated in the soft (long distance) limit.
High-energy behavior of total cross sections is discussed in experiment and theory. Origin and meaning of the Froissart bounds are described and explained. Violation of the familiar log-squared bound appears to not violate unitarity (contrary to the common opinion), but correspond to rapid high-energy increase of the amplitude in nonphysical regions.
We discuss a model for soft gluon re-summation based on a statistical description of independent emissions during inelastic collisions. The model is applied to estimate Survival Probabilities at the LHC. A comparison with other models and experimental data is presented.
A previously successful model for purely hadronic total cross-sections, based on QCD minijets and soft-gluon resummation, is here applied to the total photoproduction cross section. We find that our model in the gamma p case predicts a rise with energy stronger than in the pp -pbarp case.
We present an estimate of survival probability from an eikonal mini- jet model implemented with a proposal for soft gluon resummation to all orders. We compare it with experimental data for diffractive di-jet production from LHC experiments, CMS and ATLAS, both at LO and NLO order.
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.