Prima Facie Evidence against Spin-Two Higgs Impostors

TL;DR

This paper provides evidence against the hypothesis that the new particle X is a spin-two graviton-like impostor, based on its decay coupling ratios to vector bosons and photons, challenging certain extra-dimensional models.

Contribution

It demonstrates that graviton-like models with warped extra dimensions are strongly disfavored by current decay coupling measurements of the X particle.

Findings

Graviton-like Higgs impostor scenarios are excluded due to coupling ratio inconsistencies.

Universal couplings to photons and gluons are disfavored in these models.

Data supports the spin-zero hypothesis over spin-two models.

Abstract

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.