Revisiting ZZ and \gamma Z production with effective field theories

TL;DR

This paper provides a comprehensive effective field theory analysis of new physics effects in ZZ and gamma Z production, highlighting distinctive signatures and potential deviations from the Standard Model at high energies.

Contribution

It systematically analyzes polarization-dependent cross sections and identifies unique phenomenological signatures of new physics in ZZ and gamma Z production.

Findings

nTGC effects are suppressed at NNLO but dominate certain polarization channels at high energies.

Deviations up to 20% from the Standard Model are possible at energies around 0.6-1 TeV.

nTGC effects are significantly different from those in WW production.

Abstract

A complete and systematic effective field theory analysis of new physics effects in \bar{f}f -> ZZ and \bar{f}f -> \gamma Z is performed. Results are presented for the different initial and final-state polarized differential cross sections in terms of oblique, gauge-fermion and neutral triple gauge corrections (nTGC). Phenomenological signatures for new physics detection at the LHC and at future linear colliders are discussed. In comparison to WW production, they follow a completely different pattern: nTGC only appear at NNLO in the effective field theory expansion and, accordingly, are extremely suppressed. However, in the high energy regime, v << \sqrt{s} << 3 TeV, nTGC are shown to neatly dominate the longitudinal-transversal final-state polarizations over the standard model background. Their tiny effects get hugely amplified at energies \sqrt{s} (0.6-1) TeV and can easily generate up to 20% deviations over the standard model predictions.