Note on 125 GeV Spin-2 particle

TL;DR

This paper explores the hypothesis that the 125 GeV boson is a spin-2 graviton-like particle, analyzing its decay phenomenology and proposing methods to distinguish it from the Higgs boson.

Contribution

It introduces a spin-2 graviton-like model for the 125 GeV boson and compares its decay signatures with those of the Higgs, proposing new observables for differentiation.

Findings

Calculated three-body decay rates of the spin-2 particle

Estimated couplings between the spin-2 particle and SM gauge bosons

Proposed a new observable to distinguish spin-2 from Higgs boson

Abstract

A new boson around 125 GeV without specific spin has been observed by both ATLAS and CMS at the LHC. Since its decay into a diphoton excludes the spin-1 case by the Landau-Yang theorem,it leaves 0 or 2 as the possible lowest spin for the new boson. Instead of the well-established spin-0 Higgs-like boson, we take this new boson to be a spin-2 massive Graviton-like particle denoted as $G$, which exists copiously in extra-dimension theories, and concentrate on its phenomenology. In particular, we calculate the three-body decays of $G\rightarrow V f\bar{f}'$ with $V$ and $f^{(\prime)}$ the gauge boson and fermions in the standard model (SM) and compare our results with those of the SM Higgs boson. The couplings between $G$ and $V$s are also estimated by fitting the data. A new observable that can distinguish $G$ from the Higgs is proposed.