A Higgs Impostor in Low-Scale Technicolor

Abstract

We propose a "Higgs impostor" model for the 125 GeV boson, $X$, recently discovered at the LHC. It is a technipion, $η_T$, with $I^G J^{PC} = 0^- 0^{-+}$ expected in this mass region in low-scale technicolor. Its coupling to pairs of standard-model gauge bosons are dimension-five operators whose strengths are determined within the model. It is easy for the gluon fusion rate $σB(gg \to η_T \to γγ)$ to agree with the measured one, but $η_T \to ZZ^*,\,WW^*$ are greatly suppressed relative to the standard-model Higgs rates. This is a crucial test of our proposal. In this regard, we assess the most recent data on $X$ decay modes, with a critical discussion of $X \to ZZ^* \to 4\ell$. In our model the $η_T$ mixes almost completely with the isovector $π^0_T$, giving two similar states, $η_L$ at 125 Gev and $η_H$ higher, possibly in the range 170--190 Gev. Important consequences of this mixing are (1) the only associated production of et al is via $\to \to W η_L$, and this could be sizable; (2) $η_H$ may soon be accessible in $gg \to η_H \to γγ$; and (3) LSTC phenomenology at the LHC is substantially modified.

25 pages, 9 figures, references added. Our discussion of the 125 GeV boson discovered at CERN is updated to include the latest ATLAS and CMS data. We critically examine the crucial ZZ* -> 4l data and argue that it does not justify identifying this boson as a Higgs. In addition, several minor corrections have been made