Hadron properties and meson mixing effects in hot and dense strongly interacting matter

Le résumé fourni par la source

In the present thesis, the properties of hadrons in a dense medium are studied. The collective excitations related to the propagation of scalar and vector mesons in dense nuclear matter are discussed in a relativistic mean field model. Finite temperature effects on the meson properties in nuclear matter are also considered. One of the main concerns of the present thesis is the evaluation of symmetry-breaking effects induced by the dense matter. Special emphasis is put on the study of scalar-vector meson mixing effect, a pure density-dependent effect forbidden in vacuum on account of the Lorentz symmetry. In this direction, a new symmetry-breaking effect---the rho-a 0 meson mixing---is revealed and studied in detail along with a similar effect induced by the o-sigma mixing. The possibility of a new dilepton channel, arising from pi-eta collisions and mediated by rho-a 0 mixing, is further discussed in a relativistic kinetic model. The effects of o-sigma mixing on the amplitude of the dilepton production process from pion annihilation is also evaluated in a similar manner. The possibility of observing such symmetry-breaking effects in nucleus-nucleus collision experiments is investigated. For the space-time evolution of the matter formed during the collision, a thermal model is employed and the equation of state is determined from the interacting nuclear matter within the scope of a mean field model. We argue that such processes can be observed in the dilepton spectra at GSI/SIS energies, while they are not so evident at higher energy experiments performed at CERN/SPS.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.