The Fourth Generation Quark and the 750 GeV Diphoton Excess

Abstract

Recently, the CMS and ATLAS collaborations have reported a diphoton peak at 750 GeV in the RunII of LHC at 13 TeV. We assume that the heavy fourth generation quark doublet $z,y$ with $380$GeV mass, and the width of $z,t$ is much less $b$ quark. Then we show that the contributions of the $(z\bar{z}+y\bar{y})/\sqrt{2}$ bound state ${\eta }_{zy}(1S)$ to the diphoton measurements through $\sigma (pp\to {\eta }_{zy}(1s)\to \gamma \gamma )$ are $5.6_{-2.8}^{+5.6}\mathrm{fb}$ at $\sqrt{S}=13$ TeV. They are constant with the 750 GeV diphoton excess measured by the CMS ant ATLAS collaborations.