Flavorful Z′ Signatures at LHC and ILC

Abstract

There are lots of new physics models which predict an extra neutral gauge boson, referred as Z′-boson. In a certain class of these new physics models, the Z′-boson has flavor-dependent couplings with the fermions in the Standard Model (SM). Based on a simple model in which couplings of the SM fermions in the third generation with the Z′-boson are different from those of the corresponding fermions in the first two generations, we study the signatures of Z′-boson at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). We show that at the LHC, the Z′-boson with mass around 1 TeV can be produced through the Drell–Yan processes and its dilepton decay modes provide us clean signatures not only for the resonant production of Z′-boson but also for flavor-dependences of the production cross sections. We also study fermion pair productions at the ILC involving the virtual Z′-boson exchange. Even though the center-of-energy of the ILC is much lower than a Z′-boson mass, the angular distributions and the forward–backward asymmetries of fermion pair productions show not only sizable deviations from the SM predictions but also significant flavor-dependences.