Diboson excess in the Higgs singlet and vector-like quark models

Understand

Diboson resonance with mass of $1.8-2$ TeV is reported successively by CMS and ATLAS experiments in proton-proton collisions at $\sqrt{s}=8$ TeV.

• We investigate the potentiality of Higgs singlet as the TeV resonance.
• The challenges of low production cross section and high width for a fundamental scalar could be got over by three factors: (1) larger Yukawa couplings, (2) larger number of heavy quarks and (3) smaller mixing angle with standard model Higgs.
• We find that the required factors could be realized in the framework of two vector-like triplet quarks (VLTQs) and the resulting production cross section and decay fraction of heavy Higgs $\sigma(pp\to H )\times {\rm BR}(H\to W^+ W^- + ZZ)$ can be of ${\cal O}(10)$ fb when masses of new heavy quarks are 1 TeV, the values of Yukawa couplings are around $3$ and the mixing angle is $\sin\theta \sim 0.11$.