New Physics Contribution to Neutral Trilinear Gauge Boson Couplings

Abstract

We study the one loop new physics effects to the CP even triple neutral gauge boson vertices ${\gamma }^{\star }\gamma Z$, ${\gamma }^{\star }ZZ$, $Z^{\star }Z\gamma$ and $Z^{\star }ZZ$ in the context of Little Higgs models. We compute the contribution of the additional fermions in Littles Higgs model in the framework of direct product groups where $[SU(2)\times U(1){]}^2$ gauge symmetry is embedded in SU(5) global symmetry and also in the framework of simple group where $SU(N)\times U(1)$ gauge symmetry breaks down to $SU(2{)}_L\times U(1)$. We calculate the contribution of the fermions to these couplings when $T$ parity is invoked. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a' and compare with the SM and Little Higgs models.

Comments: 19 pages, 5 figures, 3 tables