Signals of additional Z boson in e+e-\to W+W^- at the ILC with polarized beams

TL;DR

This paper investigates how polarized electron-positron collisions at the ILC can reveal heavy Z' bosons predicted by extensions of the standard model, through deviations in various observables at high energies.

Contribution

It demonstrates the potential of polarized beams at the ILC to detect and distinguish heavy Z' bosons via specific measurable deviations from standard model predictions.

Findings

Significant deviations in cross sections and angular distributions at 800 GeV with polarized beams.

Forward-backward asymmetry and lepton fractions are highly sensitive to new physics.

Polarized beams enhance the ability to discriminate between different Z' models.

Abstract

We consider the possibility of fingerprinting the presence of heavy additional Z' bosons that arise naturally in extensions of the standard model such as E_6 models and left-right symmetric models, through their mixing with the standard model Z boson. By considering a class of observables including total cross sections, energy distributions and angular distributions of decay leptons we find significant deviation from the standard model predictions for these quantities with right-handed electrons and left-handed positrons at \sqrt{s}=800 GeV. The deviations being less pronounced at smaller centre of mass energies as the models are already tightly constrained. Our work suggests that the ILC should have a strong beam polarization physics program particularly with these configurations. On the other hand, a forward backward asymmetry and lepton fraction in the backward direction are more sensitive to new physics with realistic polarization due to interesting interplay with the neutrino t- channel diagram. This process complements the study of fermion pair production processes that have been considered for discrimination between these models.