Recherche-intervention en développement durable

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 ▲]

A model for the generalized parton distribution of the pion

in AIP Conference Proceedings (2005), 756

A model for the off-forward structure functions of the pion

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 ▲]

Pion Structure Function and violation of the Momentum Sum Rule

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 ▲]

A model for the pion structure function

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 ▲]

Neutral Pion Structure Function

Conference (2001)

Chiral theory of mesons in dense baryonic matter (I)

in Nuclear Physics A (1992), 537

Chiral mesons in dense nuclear matter

in Nuclear Physics A (1989), 504