LHC signatures of a Z' mediator between dark matter and the SU(3) sector

Abstract

In this paper, we study the experimental signatures of a gluophilic $Z^{\prime }$ at the LHC, in particular through the analysis of three jets or four tops events. The $Z^{\prime }$ couples to gluons through dimension six operators and the parameter space is constrained with experimental searches released at 7 and 8 $\mathrm{TeV}$ by CMS along these two different channels. Existing constraints coming from the study of dark matter where the $Z^{\prime }$ represents a possible mediator between the latter and the Standard Model are also included for comparison. Prospects at $\sqrt{s}=13$ TeV allow us to evaluate for which values of the parameter space a gluophilic $Z^{\prime }$ could be discovered during the next run of the LHC. In particular, we show that the analysis of the three jets invariant mass could provide a clear signal ($>5\sigma$) for masses of the $Z^{\prime }$ above 300 $\mathrm{GeV}$. Four tops events bring in addition further discovery potential for heavy $Z^{\prime }$ (above $\sim 2\mathrm{TeV}$). A combination of both signals in four top channels and three jets analyses during the next run of the LHC could thus provide a clear signal of the presence of a heavy gluophilic $Z^{\prime }$.

Comments: 17 pages, 6 figures