Heavy quarkonium production in high-energy hadronic collisions

by Lansberg, J.-Ph. (Ecole Polytechnique - CPHT Palaiseau)

Friday 29 Sept 2006, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

In the first part, I shall give a review of the existing models describing heavy-quarkonium production in high-energy hadronic collisions, namely the Colour-Singlet Model (CSM), the Colour-Octet Mechanism, the Colour-Evaporation Model (CEM), the SCI Model, the kT factorisation and the Co-mover Enhancement Scenario (CES). Then, I shall expose how it is possible to extend the CSM beyond its static limit. I shall show how this extension can break gauge invariance and I shall explain how the latter can be restored by introducing 4-point vertices. Finally, I will expose the results of our approach, by emphasising that there exists an ambiguity in the definition of those vertices and that this can be exploited in order to put our theoretical description in agreement with experimental measurements by CDF and PHENIX.