Model-independent search for the Abelian Z' boson in the Bhabha process
  Model-independent observables to pick out the Abelian Z' signal in the Bhabha process are introduced at energies >= 200 GeV. They measure separately the Z'-induced vector and axial-vector four-fermion contact couplings. The analysis of the LEP2 data constrains the value of the Z'-induced vector four-fermion coupling at the 2-sigma confidence level that corresponds to the Abelian Z' boson with the mass of order 1 TeV. 
A.V. Gulov and V.V. Skalozub (Dniepropetrovsk National University)