Production cross section estimates for strongly-interacting Electroweak Symmetry Breaking Sector resonances at particle colliders

TL;DR

This paper estimates production cross sections for hypothetical strongly-interacting electroweak resonances at colliders, exploring their potential signals and compatibility with current experimental excesses.

Contribution

It provides simple, model-based estimates for EWSBS resonance production at colliders, including the effects of unitarity and effective field theory extensions.

Findings

Resonance production rates are close to current experimental bounds.

A 2 TeV isovector resonance could explain some collider excesses.

Additional physics may be needed to account for certain observed anomalies.

Abstract

We are exploring a generic strongly-interacting Electroweak Symmetry Breaking Sector (EWSBS) with the low-energy effectie field theory for the four experimentally known particles ($W_L^\pm$, $Z_L$, $h$) and its dispersion-relation based unitary extension. In this contribution we provide simple estimates for the production cross section of pairs of the EWSBS bosons and their resonances at proton-proton colliders as well as in a future $e^-e^+$ (or potentially a $\mu^-\mu^+$) collider with a typical few-TeV energy. We examine the simplest production mechanisms, tree-level production through a $W$ (dominant when quantum numbers allow) and the simple effective boson approximation (in which the electroweak bosons are considered as collinear partons of the colliding fermions). We exemplify with custodial isovector and isotensor resonances at 2 TeV, the energy currently being discussed because of a slight excess in the ATLAS 2-jet data. We find it hard, though not unthinkable, to ascribe this excess to one of these $W_LW_L$ rescattering resonances. An isovector resonance could be produced at a rate smaller than, but close to earlier CMS exclusion bounds, depending on the parameters of the effective theory. The $ZZ$ excess is then problematic and requires additional physics (such as an additional scalar resonance). The isotensor one (that would describe all charge combinations) has a smaller cross section.