Effective Field Theory Analysis of New Physics in e+e- -> W+W- at a Linear Collider

TL;DR

This paper investigates how new physics could affect W+W- production in electron-positron collisions at TeV energies using an effective field theory approach, providing detailed calculations and interpretations relevant for future collider experiments.

Contribution

It develops a comprehensive effective field theory framework for analyzing new physics effects in e+e- -> W+W-, including operator basis, polarization effects, and model examples.

Findings

Corrections grow with energy and are expressed via modified gauge-fermion couplings.

Explicit calculations of polarized cross sections at high energies.

Discussion of implications for LHC W+W- production.

Abstract

We analyze new physics contributions to $e^+e^-\to W^+W^-$ at the TeV energy scale, employing an effective field theory framework. A complete basis of next-to-leading order operators in the standard model effective Lagrangian is used, both for the nonlinear and the linear realization of the electroweak sector. The elimination of redundant operators via equations-of-motion constraints is discussed in detail. Polarized cross sections for $e^+e^-\to W^+W^-$ (on-shell) are computed and the corrections to the standard model results are given in an expansion for large $s/M^2_W$. The dominant relative corrections grow with $s$ and can be fully expressed in terms of modified gauge-fermion couplings. These corrections are interpreted in the context of the Goldstone boson equivalence theorem. Explicit new physics models are considered to illustrate the generation and the potential size of the coefficients in the effective Lagrangian. Brief comments are made on the production of $W^+W^-$ pairs at the LHC.