Non-universality of transverse Coulomb exchange at small x

Joerg Aichelin (1) , F. Arleo (2) , Pol-Bernard Gossiaux (1) , Thierry Gousset (1) , S. Peigne (3) , M. Thomas (1)

1 SUBATECH - Laboratoire SUBATECH Nantes
2 LPTHE - Laboratoire de Physique Théorique et Hautes Energies
3 LAPTH - Laboratoire d'Annecy-le-Vieux de Physique Théorique

Within an explicit scalar QED model we compare, at fixed x << 1, the leading-twist K_T-dependent `quark' distribution f_q(x, K_T) probed in deep inelastic scattering and Drell-Yan production, and show that the model is consistent with the universality of f_q(x, K_T). The extension of the model from the aligned-jet to the 'symmetric' kinematical regime reveals interesting properties of the physics of Coulomb rescatterings when comparing DIS and DY processes. At small x the transverse momentum induced by multiple scattering on a single centre is process dependent, as well as the transverse momentum broadening occurring in collisions on a finite size nuclear target.

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]

Joerg Aichelin, F. Arleo, Pol-Bernard Gossiaux, Thierry Gousset, S. Peigne, et al.. Non-universality of transverse Coulomb exchange at small x. Physical Review D, 2005, 72, pp.054010. ⟨10.1103/PhysRevD.72.054010⟩. ⟨hal-00008910⟩