[SEMINARI] SEMINAR: Mathieu Vincent, Semi-relativistic potential model for low-lying three-gluon glueballs

[German Rodrigo Garcia]

Semi-relativistic potential model for low-lying three-gluon glueballs

Mathieu Vincent
UNiversite de Mons-Hainaut, Belgium
Friday, 15 of December of 2006     12:00 PM
Theoretical Physics Seminars room

Abstract

The Quantum Chromodynamic (QCD) is the modern theory of the strong 
interaction. The QCD allows the coupling of gluons, the gauge particles of 
the interaction, which can in theory form a observable state. These bound 
states of gluons are called glueballs. The glueballs haven't been observed 
yet but it seems that they mix strongly with the light mesons in observed 
states. The glueballs spectrum deserved interest for the understanding of 
such exotic system. We propose to study the spectrum of the three-gluon 
glueballs from the point of view of the potential models. In this 
approach, the spectrum is given by the eigenvalues of a Hamiltonian. This 
Hamiltonian is the sum of a semi-relativistic kinetic operator and a 
potential. In QCD, the potential is given by the sum of a perturbative 
part arising from a non relativistic reduction of Feynman diagrams at 
lower order and a confining potential simuling the non perturbative part 
of the interaction. We consider effective gluons with a mass given by the 
confinement and with a size to avoid problems induced by the perturbative 
part of the potential. The Hamiltonian depends on three parameters : the 
strong coupling constant, the string tension and the gluon size. These 
parameters was fitted on the two-gluon glueballs. Our spectrum for the 
three-gluon glueballs are in good agreement with the lattice results. 
[V.~Mathieu, C.~Semay and B.~Silvestre-Brac, Phys.\ Rev.\ D {\bf 74} 
(2006) 054002 hep-ph/0605205]