Jakob Beyer: WW/ZZ separation in their hadronic decays at the ILC

Electroweak precision measurements at an e⁺e^- collider are the next step in testing the Standard Model - and complementary to the LHC. Such measurements can be provided at the future International Linear Collider (ILC). Its polarized electron and positron beams, the precise event reconstruction using state-of-the-art detectors as well as the excellent theoretical calculability present an ideal environment for this enterprise. 

The baseline design of the ILC provides a center-of-mass energy of 250GeV but extensions up to 1TeV are possible. With such an extension additional important physics measurements, e.g.\ of the quartic gauge coupling, could be performed. At the ILC, these studies can include the dominant hadronic decay modes of the W and Z due to the low QCD background. Even VBS-like signatures like e⁺e^- →vv WW / vv ZZ are then accessible in their hadronic final states, allowing for a significant increase in signal events. For such measurements the separability of the W and Z decays to two jets is important and constitutes a benchmark for the detectors.

A study of this separation power at International Large Detector is performed in the case of diboson (WW/ZZ)+vv events at the center of mass energy of 1 TeV ILC.