Browse ORBi by ORBi project

- Background
- Content
- Benefits and challenges
- Legal aspects
- Functions and services
- Team
- Help and tutorials

Soft and hard Pomerons in hadron elastic scattering at small t Cudell, Jean-René ; ; in Physical Review. D (2006), 73(3), We consider simple-pole descriptions of soft elastic scattering for pp, (p) over barp, pi(+/-)p and K(+/-)p. We work at t and s small enough for rescatterings to be effectively absorbed in a simple-pole ... [more ▼] We consider simple-pole descriptions of soft elastic scattering for pp, (p) over barp, pi(+/-)p and K(+/-)p. We work at t and s small enough for rescatterings to be effectively absorbed in a simple-pole parametrization, and allow for the presence of a hard Pomeron. After building and discussing an exhaustive dataset, we show that simple poles provide an excellent description of the data in the region -0.5 GeV2<= t <= -0.1 GeV2, 6 GeV <= root s <= 63 GeV. We show that new form factors have to be used, and get information on the trajectories of the soft and hard Pomerons. [less ▲] Detailed reference viewed: 11 (4 ULg)Soft data and the hard pomeron Cudell, Jean-René ; ; et al in Nuclear Physics B-Proceedings Supplements (2006, February), 152 We show that the introduction of an additional, hard, singularity in soft forward amplitudes enables one to improve considerably the fits using a simple-pole structure for the soft pomeron. Detailed reference viewed: 18 (8 ULg)Analytic properties of unitarization schemes ; Cudell, Jean-René in Czechoslovak Journal of Physics (2006) The analytic properties of the elastic hadron scattering amplitude are examined in the impact parameter representation at high energies. Different unitarization procedures and the corresponding non-linear ... [more ▼] The analytic properties of the elastic hadron scattering amplitude are examined in the impact parameter representation at high energies. Different unitarization procedures and the corresponding non-linear equations are presented. Several unitarisation schemes are presented. They lead to almost identical results at the LHC. [less ▲] Detailed reference viewed: 614 (72 ULg)Saturation effects in diffractive scattering at LHC energies ; Cudell, Jean-René in Kolganova, E.; Sissakian, A.; Kozlov, G. (Eds.) ICHEP 2006: Proceedings (2006) Detailed reference viewed: 2 (0 ULg)Comparison of different non-linear equations and corresponding unitarization schemes ; Cudell, Jean-René in Proceedings of science (2006) Detailed reference viewed: 3 (0 ULg)Saturation effects in pp scattering in the impact-parameter representation ; Cudell, Jean-René in Nuclear Physics B-Proceedings Supplements (2005, September), 146 The impact of unitarity is considered in different approaches to saturation in impact-parameter space. The energy and momentum-transfer dependence of the total and differential cross sections and of the ... [more ▼] The impact of unitarity is considered in different approaches to saturation in impact-parameter space. The energy and momentum-transfer dependence of the total and differential cross sections and of the ratio of the real to imaginary parts of the scattering amplitude are obtained in a model that includes soft and hard pomeron contributions, coupled to hadrons via the electromagnetic form factor. It is shown that the hard pomeron may significantly contribute to soft physics at the LHC. A similar conclusion can also be reached in the framework of non-linear approaches to unitarisation of the BFKL pomeron. [less ▲] Detailed reference viewed: 29 (2 ULg)Direct extraction of hadronic form factors from elastic-scattering data ; Cudell, Jean-René ; in Nuclear Physics B-Proceedings Supplements (2005, September), 146 Non-forward elastic hadron-scattering data are collected and analysed within the Regge approach. Through an analysis of the data in small bins in t, we have directly extracted the pomeron trajectory and ... [more ▼] Non-forward elastic hadron-scattering data are collected and analysed within the Regge approach. Through an analysis of the data in small bins in t, we have directly extracted the pomeron trajectory and the hadronic form factors (or reggeon couplings). We found higher values than usually used for the intercept and for the slope of the soft pomeron trajectory. The presence of zeros in t for the effective hadronic form factors is emphasised. [less ▲] Detailed reference viewed: 14 (1 ULg)HLPR 2004: Hadronic Physics: Joint meeting Heidelberg- Liege-Paris-Rostock Lansberg, Jean-Philippe ; Cudell, Jean-René ; Cugnon, Joseph Book published by American Institute of Physics - AIP Conference Proceedings (2005) Detailed reference viewed: 17 (5 ULg)A Review of the hard pomeron in soft diffraction Cudell, Jean-René ; ; et al in Nuclear Physics A (2005), 755 We review the evidence for the presence of a hard singularity in soft forward amplitudes, and give an estimate of its trajectory and couplings. Detailed reference viewed: 52 (11 ULg)A toy model for generalised parton distributions Cudell, Jean-René ; ; Cugnon, Joseph et al in AIP Conference Proceedings (2005), 775 Detailed reference viewed: 34 (3 ULg)Impact of saturation on spin effects in proton-proton scattering ; Cudell, Jean-René in Czechoslovak Journal of Physics (2005), 55(Suppl. A), 235-242 For pomerons described by a sum of two simple-pole terms, a soft and a hard pomeron, the unitarity bounds from saturation in impact-parameter space are examined. We consider the effect of these bounds on ... [more ▼] For pomerons described by a sum of two simple-pole terms, a soft and a hard pomeron, the unitarity bounds from saturation in impact-parameter space are examined. We consider the effect of these bounds on observables linked with polarisation, such as the analyzing power A(N) in elastic proton-proton scattering, for LHC energies. We obtain the s and t dependence of the Coulomb-nuclear interference at small momentum transfer, and show that the effect of the hard pomeron may be observed at the LHC. [less ▲] Detailed reference viewed: 18 (1 ULg)A model for the generalized parton distribution of the pion Stassart, Pierre ; ; Cudell, Jean-René et al in AIP Conference Proceedings (2005), 756 Detailed reference viewed: 19 (3 ULg)Hard pomeron contribution to forward elastic scattering Cudell, Jean-René ; ; et al in Nicolescu, B. (Ed.) Conference On Elastic And Diffractive Scattering: Towards High Energy Frontiers: The 20th Anniversary Of The Blois Workshops (2005) Detailed reference viewed: 11 (1 ULg)Elastic meson nucleon and nucleon nucleon scattering: Models vs. all available data ; Cudell, Jean-René ; in Nicolescu, B. (Ed.) 11th International Conference On Elastic And Diffractive Scattering: Towards High Energy Frontiers: The 20th Anniversary Of The Blois Workshops (2005) Detailed reference viewed: 13 (0 ULg)High-energy hadron spin-flip amplitude at small momentum transfer and new A(N) data from RHIC Cudell, Jean-René ; ; in European Physical Journal A -- Hadrons & Nuclei (2004), 21(3), 479-486 In the case of elastic high-energy hadron-hadron scattering, the impact of the large-distance contributions on the behaviour of the slopes of the spin-non-flip and of the spin-flip amplitudes is analysed ... [more ▼] In the case of elastic high-energy hadron-hadron scattering, the impact of the large-distance contributions on the behaviour of the slopes of the spin-non-flip and of the spin-flip amplitudes is analysed. It is shown that the long tail of the hadronic potential in impact parameter space leads to a value of the slope of the reduced spin-flip amplitude larger than that of the spin-non-flip amplitude. This effect is taken into account in the calculation of the analysing power in proton-nucleus reactions at high energies. It is shown that the preliminary measurement of A(N) (for p 12C obtained by the E950 Collaboration indeed favours a spin-flip amplitude with a large slope. Predictions for A)(N) (at P)(L) = 250 GeV/c are given. [less ▲] Detailed reference viewed: 30 (9 ULg)Generalized parton distributions of the pion ; Cudell, Jean-René ; Cugnon, Joseph et al in Nuclear Physics B-Proceedings Supplements (2004, July), 133 Off-forward structure functions of the pion are investigated in twist-two and twist-three approximation. A simple model is used for the pion, which allows to introduce finite size effects, while ... [more ▼] Off-forward structure functions of the pion are investigated in twist-two and twist-three approximation. A simple model is used for the pion, which allows to introduce finite size effects, while preserving gauge invariance. Results for the imaginary parts of the gamma*pi --> gamma*pi off-forward amplitude and of the structure functions are presented. Generalized Callan-Gross relations are obtained. [less ▲] Detailed reference viewed: 21 (8 ULg)A model for the off-forward structure functions of the pion ; Cudell, Jean-René ; Cugnon, Joseph et al in Physics Letters B (2004), 587(3-4), 189-200 We extend our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward y*pi -->. gamma*pi scattering ... [more ▼] We extend our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward y*pi -->. gamma*pi scattering amplitude is evaluated in the chiral limit (m(pi) = 0) and related to the twist-two and twist-three generalised parton distributions H, H-3, (H) over tilde (3). Non-perturbative effects, linked to the size of the pion and still preserving gauge invariance, are included. Remarkable new relations between H, H3 and (H) over tilde (3) are obtained and discussed. (C) 2004 Published by Elsevier B.V. [less ▲] Detailed reference viewed: 17 (3 ULg)The hard pomeron in soft data Cudell, Jean-René ; ; et al in Physics Letters B (2004), 587(1-2), 78-86 We show that the data for the total cross section and for the real part of the elastic amplitude indicate the presence of a hard pomeron in pip and Kp elastic scattering at t = 0, compatible with that ... [more ▼] We show that the data for the total cross section and for the real part of the elastic amplitude indicate the presence of a hard pomeron in pip and Kp elastic scattering at t = 0, compatible with that observed in deep inelastic scattering. We show that such a hard pomeron is also compatible with pp and pp data, provided one unitarises it at high energy. (C) 2004 Published by Elsevier B.V. [less ▲] Detailed reference viewed: 17 (7 ULg)t-channel unitarity and photon cross sections Cudell, Jean-René ; ; in Nuclear Physics B (2004), 682(1-2), 391-420 We analyse the consequences of t-channel unitarity for the photon hadronic cross sections. We show that gamma((*))p and gamma((*))gamma((*)) elastic amplitudes must include the complex-j plane ... [more ▼] We analyse the consequences of t-channel unitarity for the photon hadronic cross sections. We show that gamma((*))p and gamma((*))gamma((*)) elastic amplitudes must include the complex-j plane singularities associated with hadronic elastic amplitudes, and give the characteristics of possible new singularities. We also show that several different models of hadronic total cross sections can be used to predict the LEP data from the HERA measurements. (C) 2004 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 17 (4 ULg)Hadron spin-flip amplitude: an analysis of the new A(N) data from RHIC Cudell, Jean-René ; in Czechoslovak Journal of Physics (2004), 54(Suppl. B), 161-166 Through a direct analysis of the scattering amplitude, we show that the preliminary measurement of AN obtained by the E950 Collaboration at different energies leads to the large slope of the scattering ... [more ▼] Through a direct analysis of the scattering amplitude, we show that the preliminary measurement of AN obtained by the E950 Collaboration at different energies leads to the large slope of the scattering amplitude and are mainly sensitive to the chosen of the energy behavior of the p(s,t). [less ▲] Detailed reference viewed: 14 (3 ULg) |
||