Production and Decay of 750 Gev state of 6 top and 6 anti top quarks

Abstract

Crude estimates are made of the branching ratios and pair production cross-section for our previously proposed bound state S of six top and six antitop quarks identified with the diphoton excess recently observed in ATLAS and CMS. We estimate the pair production cross section to be approximately 12 times that for fourth family quarks. Hence we predict $\sigma(pp \rightarrow SS + anything) \approx 2$ pb at 13 TeV and an increase by a factor 10 over the cross section at 8 TeV. Crude estimates of the main branching ratios relative to the diphoton decay give $\Gamma(S\rightarrow \gamma+\gamma) \propto 1$, $\Gamma(S\rightarrow t + \bar{t})\propto 378$, $\Gamma(S \rightarrow gluon+gluon)\propto 117$, $\Gamma(S\rightarrow Higgs+Higgs)\propto 15$, $\Gamma(S\rightarrow W+W)\propto 30$ and $\Gamma(S\rightarrow Z+Z) = 15$. These estimates are consistent with the LHC bounds at 8 TeV within a factor 1.25. We expect the $S \rightarrow \gamma\gamma$ events to be produced together with another S resonance decaying typically into top-antitop or gluon-gluon jets.