LHCP 2013 - First Large Hadron Collider Physics Conference

On equivalence of gluon-loop exchange in the inelastic processes in perturbative QCD to pion exchange in phi^3 theory

Not scheduled

20m

Hotel Catalonia Barcelona Plaza, Barcelona - Spain

Theory Poster

Speaker

Mr Andrii Tykhonov (Institute Jozef Stefan, Ljubljana, Slovenia)

Description

We consider the hadron-hadron inelastic scattering in the framework of QCD perturbation theory. It is shown that in QCD due to conservation of colour it is prohibitive to consider tree-level diagrams of inelastic scattering and one has to consider the diagrams with loops. We examine the simplest type of such diagrams, where the diagram can be split into blocks, so that the integration over four-momenta of virtual particles in each block is done independently of the other blocks. It is shown that for these diagrams the squared modulus of scattering amplitude has a point of maximum, similar to that of [Sharf et. al. arXiv:1110.4945], if one takes into account the relations between the arguments of scattering amplitude, imposed by the energy-momentum conservation law. This enables to apply the Laplace’s method for the calculation of inelastic-scattering cross sections. It is shown that the diagrams of gluon-loop exchange in QCD are equivalent to the diagrams of pion exchange in \phi^3 theory, whereby the new mechanism of cross-section growth, discovered in \phi^3 theory [Sharf et. al. arXiv:1110.4945], also takes place in erturbative QCD. This may explain the origin of experimentally-observed growth of inelastic-scattering cross section as a function of energy of colliding hadrons [ALICE collaboration, arXiv:1109.4510]. The discovered mechanism can’t emerge in any Regge-based model due to the premises on the particle kinematics, made in these models.