Heavy Higgs Coupled to Vector-like Quarks: Strong CP Problem and Search Prospects at the 14 TeV LHC

Abstract

Motivated by a solution to the strong CP problem we propose a model where a new heavy neutral CP-even Higgs boson couples to vector-like quarks enhancing its production cross section whose dominant decays are into weak bosons. The masses of the vector-like quarks are generated through interactions with a singlet scalar field charged under a broken global $U(1)$ symmetry providing a solution to the strong CP problem by means of the Peccei-Quinn mechanism. The diboson excess observed by the ATLAS Collaboration is discussed as the new heavy Higgs boson is a candidate to explain a possible signal in this channel. We also show that the 14 TeV LHC is capable of discovering this heavy Higgs with masses up to 1 TeV in the $H\to ZZ\to {\ell }^{+}{\ell }^{-}{\ell }^{\prime +}{\ell }^{\prime -}$ search channel using boosted decision trees to better discriminate between signals and backgrounds and to tame systematic uncertainties in the background rates.

Comments: 21 pages, 8 figures, just a correction in Table I