Abstract
We present a new study of quasi-elastic W and Z scattering processes in high-energy e^+e^- collisions, based on and extrapolating the low-energy effective theory which extends the standard model with a 125;text {GeV} Higgs boson. We parameterize deviations in the low-energy range in terms of the dimension-eight operators that arise in the effective theory. Smoothly extending this to higher energy, we study a set of simplified models of new physics in W / Z scattering, (1) a structureless extrapolation of the effective theory, and (2) scalar and tensor resonance multiplets. The high-energy asymptotics of all models is regulated by a universal unitarization procedure. This enables us to provide benchmark scenarios which can be meaningfully evaluated off shell and in exclusive event samples, and to determine the sensitivity of an e^+e^- collider to the model parameters. We analyze the longitudinal vector-boson scattering modes, where we optimize the cuts for the fiducial cross section for different collider scenarios. Here, we choose energy stages of 1.0, 1.4 and 3 TeV, as motivated by the extendability of the ILC project and the staging scenario of the CLIC project.
Highlights
If the Higgs was missing from the particle spectrum, the W/Z interaction strength would rise with energy into a nonperturbative regime, indicating an intrinsic cutoff of the effective theory and new strong interactions [3,4]
VBS processes have been observed at the large hadron collider (LHC) in Run I [6–8], and the analysis of future LHC runs at full energy and increased luminosity will considerably improve our knowledge in this sector
The free parameters FS,0 and FS,1 are identified as expansion parameters in the effective field theory (EFT), within the range of validity of the latter
Summary
If the Higgs was missing from the particle spectrum, the W/Z interaction strength would rise with energy into a nonperturbative regime, indicating an intrinsic cutoff of the effective theory and new strong interactions [3,4]. Collider experiments will have to search for new effects in this area and complete our knowledge about the particle and interaction spectrum at accessible energies. VBS processes have been observed at the large hadron collider (LHC) in Run I [6–8], and the analysis of future LHC runs at full energy and increased luminosity will considerably improve our knowledge in this sector. We realize this program by starting with seed models that either naively continue the EFT without new structure, or include new particle states with arbitrary mass and coupling and extra free parameters. For each of these seed models, we apply a universal unitarization method, the T-matrix framework.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
