New Physics Contribution to Neutral Trilinear Gauge Boson Couplings

TL;DR

This paper investigates how new physics, specifically Little Higgs models and the MSSM, affects neutral trilinear gauge boson couplings at one loop, providing detailed calculations and comparisons with the Standard Model.

Contribution

It presents detailed one-loop calculations of neutral gauge boson couplings in Little Higgs models, including T parity effects and MSSM comparison, extending previous analyses.

Findings

New physics models modify gauge boson couplings significantly.

Fermion contributions vary with model parameters and symmetry breaking.

Comparison shows differences between MSSM, Little Higgs, and Standard Model.

Abstract

We study the one loop new physics effects to the CP even triple neutral gauge boson vertices $\gamma^\star \gamma Z$, $\gamma^\star Z Z$, $Z^\star Z \gamma$ and $Z^\star Z Z$ 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.