Model-independent constraints on the Abelian $Z^{\prime }$ couplings within the ATLAS data on the dilepton production processes at $\sqrt{s}=$ 13 TeV

Abstract

The study of lepton pair production is a powerful test of the Standard Model (SM) and can be used to search for phenomena beyond the SM. New heavy neutral bosons $Z^{\prime }$ decaying to charged lepton pairs $l^{+}{l}^{-}$ ($l=e,\mu$) are predicted by many scenarios of new physics, including models with extended gauge sector. We estimate the LHC $Z^{\prime }$ discovery potential with Run 2 data comprised of 36.1 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV and recorded by ATLAS detector at the CERN LHC. The model-independent constraints on the $Z^{\prime }$ fermion couplings were obtained for the first time for a selected set of $Z^{\prime }$ signal mass points of $M_{Z^{\prime }}=2$, 3, and 4 TeV by using the ATLAS data collected at the LHC. The analysis is based on the derived earlier special relations between the $Z^{\prime }$ couplings proper to the renormalizable theories. Taking into account the dependence of $Z-Z^{\prime }$ mixing angle ${\theta }_0$ on the $Z^{\prime }$ axial-vector coupling $a$, the limits on ${\theta }_0$ are established as ${\theta }_0<10^{-4}-10^{-3}$ in the investigated $Z^{\prime }$ mass range.

Comments: arXiv admin note: text overlap with arXiv:1803.07508; text overlap with arXiv:0909.1320, arXiv:0911.1450 by other authors