Recherche d'un Higgs doublement chargé à l'aide du détecteur ATLAS dans le cadre d'un Modèle de Symétrie Gauche-Droite

To be able to explain the fact that, in the Standard Mo del weak interactions only a ect left handed particles, it is possible to dev elop left - righ t symmetric mo dels, where the symmetry is brok en to explain the low energy spectrum. Some of these mo dels predict the existence of a doubly charged Higgs. With the future startup of the LHC, it would be possible to disco ver suc h a particle. The mo del we will discuss in this documen t uses two Higgs triplets to break the left - righ t symmetry . Those triplets imply the existence of ++ L and ++ R . We then study single pro duction by vector boson fusion and pair pro duction by a Drell-Y an pro cess for ++ L;R and their deca y in the ATLAS detector at LHC. Disco very poten tial of those particles will be tak en into accoun t for several deca y channels. We will concen trate on leptonic channels, because they pro vide clear signatures in a detector. Other mo des exist, but they are suppressed by kinematics. We nd that for vector boson fusion, the doubly charged Higgs would be ob- serv able only when it deca ys into electrons or muons. The mass limit obtained for those particles dep end on the vacuum exp ectation value of Higgs triplets. Even if the deca y mo de into taus is almost clean, the branc hing ration of the tau going to a lepton is destro ying the observ abilit y of this channel. Finally , with pair pro duction, it would be possible to x a limit on the mass of doubly charged Higgs that would not dep end on the vacuum exp ectation value, but only on the Z R mass.