ATLAS on-Z Excess Through Vector-Like Quarks

Abstract

We investigate the possibility that the excess observed in the leptonic-$Z+$jets $+\text{slashed}{E}_T$ ATLAS SUSY search is due to pair productions of a vector-like quark $U$ decaying to the first-generation quarks and $Z$ boson. We find that the excess can be explained within the 2$\sigma$ (up to 1.4$\sigma$) level while evading the constraints from the other LHC searches. The preferred range of the mass and branching ratio are $610<m_U<760$ GeV and $\mathrm{Br}(U\to Zq)>0.3$-$0.45$, respectively.

Comments: 8 pages, 2 figures