References of "Stassart, Pierre"
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See detailRecherche-intervention en développement durable
Stassart, Pierre ULg; Mormont, Marc ULg; Pichault, François ULg et al

in Pichault, François (Ed.) La recherche-intervention peut-elle être socialement responsable ? (2008)

Les questions de développement durable sont non seulemenr complexes, mais le caractère crucial de leurs enjeux suppose en outre, de la part des chercheurs en sciences sociales, une approche renouvelée de ... [more ▼]

Les questions de développement durable sont non seulemenr complexes, mais le caractère crucial de leurs enjeux suppose en outre, de la part des chercheurs en sciences sociales, une approche renouvelée de leurs analyses et de leurs interventions. Cette approche engage des processus « multistakeholders » dont la caractéristique est d'impliquer simultanément des acteurs aux caractéristiques hétérogènes qui sont dans notre cas les acteurs de la filière bovine bio. La proposition de recherche-intervention force les chercheurs à clarifier leur relation à l'objet qu'ils étudient et la qualité de leur travail dépend de la qualité et de la légitimité des traductions successives qu'ils opkrent. Ce travail suppose de prendre au sérieux la construction de nouveaux rapports entre science de la nature, recherche technique et action collective. La question de la responsabilité sociale des chercheurs est ancrée dans cette démarche, elle renvoie à une triple dimension éthique. [less ▲]

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See detailA toy model for generalised parton distributions
Cudell, Jean-René ULg; Bissey, F.; Cugnon, Joseph ULg et al

in AIP Conference Proceedings (2005), 775

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See detailA model for the generalized parton distribution of the pion
Stassart, Pierre ULg; Bissey, F.; Cudell, Jean-René ULg et al

in AIP Conference Proceedings (2005), 756

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See detailGeneralized parton distributions of the pion
Bissey, F.; Cudell, Jean-René ULg; Cugnon, Joseph ULg 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 ▲]

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See detailA model for the off-forward structure functions of the pion
Bissey, F.; Cudell, Jean-René ULg; Cugnon, Joseph ULg 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 ▲]

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See detailA simple model for generalised parton distributions of the pion
Lansberg, Jean-Philippe ULg; Bissey, F.; Cudell, Jean-René ULg et al

in Bruncko, D.; Ferencei, J.; Strizenec, P. (Eds.) 12th International Workshop On Deep Inelastic Scattering (DIS 2004) (2004)

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See detailPion Structure Function and violation of the Momentum Sum Rule
Lansberg, Jean-Philippe ULg; Bissey, F.; Cudell, Jean-René ULg et al

in Blin, A. H.; Hiller, B.; Ruivo, M. C. (Eds.) et al Hadron Physics: Effective Theories of Low Energy QCD N°2 (2003)

We present a method to evaluate the pion structure functions from a box diagram calculation. Pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The gamma^* pi -> q ... [more ▼]

We present a method to evaluate the pion structure functions from a box diagram calculation. Pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The gamma^* pi -> q \bar q cross-section is evaluated and related to the structure functions. We then show that the introduction of non-perturbative effects, related to the pion size and preserving gauge invariance, provides us with a straighforward relation with the quark distribution. It is predicted that higher-twist terms become negligible for Q^2 larger than about 2 GeV^2 and that quarks in the pion have a momentum fraction smaller than in the proton. We enlarge the discussion concerning this violation of the momentum sum rule, emphasizing that the sum rule is recovered in the chiral limit and also when the finite size condition is not imposed. [less ▲]

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See detailConfinement and cut-off: A model for the Pion Quark Distribution Function
Stassart, Pierre ULg; Bissey, F.; Cudell, Jean-René ULg et al

(2003)

The pion structure function is investigated in a simple pseudo-scalar coupling model of pion and constituent quark fields. The imaginary part of the forward Compton scattering amplitude is evaluated. We ... [more ▼]

The pion structure function is investigated in a simple pseudo-scalar coupling model of pion and constituent quark fields. The imaginary part of the forward Compton scattering amplitude is evaluated. We show that the introduction of non-perturbative effects, linked through a cut-off to the size of the pion, allows the reproduction of important features of the pion quark distribution function. [less ▲]

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See detailA model for the pion structure function
Bissey, F.; Cudell, Jean-René ULg; Cugnon, Joseph ULg et al

in Physics Letters B (2002), 547(3-4), 210-218

The pion structure function is investigated in a simple model, where pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma*pi ... [more ▼]

The pion structure function is investigated in a simple model, where pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma*pi --> gamma*pi evaluated and related to the structure functions. It is shown that the introduction of non-perturbative effects linked to the size of the pion and preserving gauge invariance, allows a connection with the quark distribution. It is predicted that higher-twist terms become negligible for Q(2) larger than similar to 2 GeV2 and that quarks in the pion have a momentum fraction smaller than in the proton case. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailThe Valence Quark Distribution of the Pion
Lansberg, Jean-Philippe ULg; Bissey, F.; Cudell, Jean-René ULg et al

in Dong Su; Burchat, Patricia (Eds.) XXII Physics in Collision Conference (PIC02) (2002)

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See detailNeutral Pion Structure Function
Cudell, Jean-René ULg; Cugnon, Joseph ULg; Jaminon, Martine ULg et al

Conference (2001)

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See detailOn the scalar meson exchange in the baryon spectra
Stassart, Pierre ULg; Stancu, Floarea ULg; Richard, J. M. et al

in Journal of Physics : G Nuclear & Particle Physics (2000), G26

We explore the role of a scalar meson exchange interaction between quarks in a semirelativistic constituent quark model where the quarks are also subject to a linear confinement. We study how the spectrum ... [more ▼]

We explore the role of a scalar meson exchange interaction between quarks in a semirelativistic constituent quark model where the quarks are also subject to a linear confinement. We study how the spectrum evolves when the strength of the scalar meson exchange increases. Our results are relevant to the long-standing problem of the relative position of the first positive-parity (Roper resonance) and the first orbitally excited states in the baryon spectrum. [less ▲]

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See detailChiral theory of mesons in dense baryonic matter (II) : Meson propagation
Jaminon, Martine ULg; Mendez Galain; Stassart, Pierre ULg

in Nuclear Physics A (1993), 556

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See detailChiral theory of mesons in dense baryonic matter (I)
Jaminon, Martine ULg; Mendez Galain, Ramon; Ripka, Georges et al

in Nuclear Physics A (1992), 537

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See detailVector mesons and partial restoration of chiral symmetry
Mendez Galain, Ramon; Ripka, Georges; Jaminon, Martine ULg et al

in Europhysics Letters [=EPL] (1991), 14

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See detailChiral mesons in dense nuclear matter
Jaminon, Martine ULg; Ripka, Georges; Stassart, Pierre ULg

in Nuclear Physics A (1989), 504

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See detailThe current quark mass and the regularisation of the Nambu-Jona-Lasinio action
Jaminon, Martine ULg; Ripka, Georges; Stassart, Pierre ULg

in Physics Letters B (1989), 227

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