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G. Pancheri

Publications and source records attributed to G. Pancheri.

At least 37 records · Page 2Linked to original sources

Soft Gluon kt-Resummation and the Froissart bound

We study soft gluon kt-resummation and the relevance of zero momentum gluons for the energy dependence of total hadronic cross-sections. We discuss a model in which consistency of the energy dependence of the cross-section with the limitation of the Froissart bound, is directly related to the behaviour of the strong coupling constant in the infrared region. Our predictions for the asymptotic behaviour are shown to be related to the ansatz that the infrared behaviour of the QCD strong coupling constant follows an inverse power law.

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QCD Mini-jet contribution to the total cross section

We present the predictions of a model for proton-proton total cross-section at LHC. It takes into account both hard partonic processes and soft gluon emission effects to describe the proper high energy behavior and to respect the Froissart bound.

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Total photoproduction cross-section at very high energy

In this paper we apply to photoproduction total cross-section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross-sections at TeV energies than models based on factorization but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.

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FASTERD: a Monte Carlo event generator for the study of final state radiation in the process $e^+e^-\toππγ$ at DA$Φ$NE

FASTERD is a Monte Carlo event generator to study the final state radiation both in the $e^+e^-\toπ^+π^-γ$ and $e^+e^-\toπ^0π^0γ$ processes in the energy region of the $ϕ$-factory DA$Φ$NE. Differential spectra that include both initial and final state radiation and the interference between them are produced. Three different mechanisms for the $ππγ$ final state are considered: Bremsstrahlung process (both in the framework of sQED and Resonance Perturbation Theory), the $ϕ$ direct decay ($e^+e^-\toϕ\to (f_0;f_0+σ)γ\to ππγ$) and the double resonance mechanism (as $e^+e^-\toϕ\to ρ^\pmπ^\mp\to π^+π^-γ$ and $e^+e^-\toρ\to ωπ^0\to π^0π^0γ$). Additional models can be incorporated as well.

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QCD and total cross-sections: photons and hadrons

In this contribution, we discuss a total cross-section model which can be applied to both photon and purely hadronic processes. We find that the model can reproduce photo-production cross-sections, as well as extrapolations of gamma* p processes to gamma p using vector meson dominance models, with minimal modifications from the proton case.

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Zero momentum gluons and the total pp and pbarp cross-sections

We describe a QCD motivated model for total cross-sections which uses the eikonal representation and incorporates QCD mini-jets to drive the rise with energy of the cross-section, while the impact parameter distribution is obtained through the Fourier transform of the transverse momentum distribution of soft gluons emitted in the parton-parton interactions giving rise to mini-jets in the final state. A singular but integral expression for the running coupling constant in the infrared region is part of this model.

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QCD Contributions to the Froissart bound for the total cross-section

We discuss the effect of infrared soft gluons on the asymptotic behaviour of the total cross-section. We use a singular but integrable expression for the strong coupling constant in the infrared limit and relate its behaviour to the satisfaction of the Froissart bound, giving a specific phenomenological example.

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Minijets, soft gluon resummation and photon cross-sections

We compare the high energy behaviour of hadronic photon-photon cross-sections in different models. We find that the photon-photon cross-section appears to rise faster than the purely hadronic ones (proton-proton and proton-antiproton).

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Large rapidity gaps survival probabilities at LHC

We calculate the probability of large rapidity gaps in high energy hadronic collisions using a model based on QCD mini-jets and soft gluon emission down into the infrared region. Comparing with other models we find a remarkable agreement among most predictions.

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Final state radiation and a possibility to test a pion-photon interaction model near two-pion threshold

Final state radiation in the process $e^+e^-\toπ^+π^-$ is considered for the cuts used in the analysis of KLOE data at large angles. By means of a Monte Carlo event generator FEVA, effects of non-pointlike behaviour of pions are estimated in the framework of Resonance Perturbation Theory. An additional complication related with the $ϕ$ meson intermediate state is taken into account and the corresponding contributions (the direct decay $ϕ\toπ^+π^-γ$ and the double resonance decay $ϕ\toρ^\pmπ^\mp\toπ^+π^-γ$) are added to FEVA. A method to test effects of non-pointlike behaviour of pions in a model-independent way is proposed.

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Prospects for e+e- physics at Frascati between the phi and the psi

We present a detailed study, done in the framework of the INFN 2006 Roadmap, of the prospects for e+e- physics at the Frascati National Laboratories. The physics case for an e+e- collider running at high luminosity at the phi resonance energy and also reaching a maximum center of mass energy of 2.5 GeV is discussed, together with the specific aspects of a very high luminosity tau-charm factory. Subjects connected to Kaon decay physics are not discussed here, being part of another INFN Roadmap working group. The significance of the project and the impact on INFN are also discussed. All the documentation related to the activities of the working group can be found in http://www.roma1.infn.it/people/bini/roadmap.html.

hep-ex↗

Test of FSR in the process $e^+e^-\toπ^+π^-γ$ at DA$Φ$NE and extraction of the pion form factor at threshold

Effects due to non-pointlike behaviour of pions in the process $e^+e^-\toπ^+π^-γ$ can arise for hard photons in the final state. By means of a Monte Carlo event generator, which also includes the contribution of the direct decay $ϕ\toπ^+π^-γ$, we estimate these effects in the framework of Resonance Perturbation Theory. We consider angular cuts used in the KLOE analysis of the pion form factor at threshold. A method to reveal the effects of non-pointlike behaviour of pions in a model-independent way is proposed.

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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.

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Les Houches Physics at TeV Colliders 2005, Standard Model and Higgs working group: Summary report

This Report summarises the activities of the "SM and Higgs" working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. On the one hand, we performed a variety of experimental and theoretical studies on standard candles (such as W, Z, and ttbar production), treating them either as proper signals of known physics, or as backgrounds to unknown physics; we also addressed issues relevant to those non-perturbative or semi-perturbative ingredients, such as Parton Density Functions and Underlying Events, whose understanding will be crucial for a proper simulation of the actual events taking place in the detectors. On the other hand, several channels for the production of the Higgs, or involving the Higgs, have been considered in some detail. The report is structured into four main parts. The first one deals with Standard Model physics, except the Higgs. A variety of arguments are treated here, from full simulation of processes constituting a background to Higgs production, to studies of uncertainties due to PDFs and to extrapolations of models for underlying events, from small-$x$ issues to electroweak corrections which may play a role in vector boson physics. The second part of the report treats Higgs physics from the point of view of the signal. In the third part, reviews are presented on the current status of multi-leg, next-to-leading order and of next-to-next-to-leading order QCD computations. Finally, the fourth part deals with the use of Monte Carlos for simulation of LHC physics.

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