Searches for anomalous tqZ couplings from the trilepton signal of tZ associated production at the 14 TeV LHC

• Published in: Physics letters. B 2018-01, Vol.776 (C), p.391-395
• Main Authors: Shen, Jie-Fen, Li, Yu-Qi, Liu, Yao-Bei
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2017.11.055

We investigate the observability of the top anomalous tqZ couplings via the trilepton signatures at the Large Hadron Collider (LHC) with the center-of-mass energy of 14 TeV. We focus on signals of the tZ associated production with the decay mode t→W+b→bℓ+νℓ, Z→ℓ+ℓ−, and tt¯ production with the decay mode t¯→Z(→ℓ+ℓ−)q¯ and t→bℓ+νℓ, where ℓ=e,μ and q reflects up and charm quarks. It is shown that at 3σ level, the FCNC top quark decay branching ratios can be probed at, respectively, about Br(t→uZ)≤1.3×10−4 and Br(t→cZ)≤4.2×10−4 with the integrated luminosity of 100 fb−1, and probed down to Br(t→uZ)≤2.2×10−5 and Br(t→cZ)≤8×10−5 for the high-luminosity LHC with 3000 fb−1.