ATLAS on-Z excess through vector-like quarks

We investigate the possibility that the excess observed in the leptonic-Z+jets+E̸TZ+jets+E̸T ATLAS SUSY search is due to productions of vector-like quarks U, which decay to the first-generation quarks and Z bosons. We find that the excess can be explained within the 2σ (up to 1.4σ  ) level with satisfying the constraints from the other LHC searches. The mass and branching ratio are 6100.3–0.45Br(U→Zq)>0.3–0.45, respectively.