Heavy quark signals from radiative corrections to the $Z^{\prime }$ boson decay in 3-3-1 models

Abstract

One-loop corrections to the $Z^{\prime }$ decay width are derived and analyzed in the framework of the general form of the 3-3-1 models. We identify two important sources of corrections: oblique corrections asociated to the $Z^{\prime }$ propagator through vacum polarizations induced by virtual particle-antiparticle pairs of new heavy quarks $J$, and vertex corrections to the $Z^{\prime }q\bar{q}$ vertex through virtual exchange of new $K^{Q_{1,2}}$ gauge bosons. Fixing an specific renormalization scheme, we obtain dominant oblique corrections that exhibit a quadratic dependence on the $J$ quark mass, which are absorbed into two oblique parameters: a global parameter ${\rho }_f^{\prime }$ which modify the $Z^{\prime }$ decay width, and a parameter ${\kappa }_f^{\prime }$ that define effective $Z^{\prime }$ couplings. Numerical results in an specific 3-3-1 model gives a strong contribution of the oblique corrections from about 1.3% in the $d(s)$ quark channel to 10.5% in the neutrino channel, for $m_J=2$ TeV. The vertex corrections contribute to the oblique corrections up to 1.4% for the same channel and $m_J$ value. For $pp$ collisions at the CERN LHC collider, we find that the corrections significantly modify the shape of the cross section distributions for $e^{+}{e}^{-}$ and $t\bar{t}$ final states, where the distributions including the radiative corrections increases up to 1.23 times the tree-level distribution for the dielectron events and to 1.07 for the top events when $m_J=3$ TeV.