Electroweak Precision Tests in High-Energy Diboson Processes

TL;DR

This paper proposes a method to test the Standard Model's electroweak sector at high energies using differential cross-section measurements in diboson processes, achieving greater sensitivity than previous bounds.

Contribution

It introduces four high-energy primary parameters to encapsulate energy-growing effects and assesses their measurement potential at current and future colliders.

Findings

Reach surpasses existing constraints by an order of magnitude.

Provides per-mille level tests of the electroweak sector.

Applicable to a broad class of new physics scenarios.

Abstract

A promising avenue to perform precision tests of the SM at the LHC is to measure differential cross-sections at high invariant mass, exploiting in this way the growth with the energy of the corrections induced by heavy new physics. We classify the leading growing-with-energy effects in longitudinal diboson and in associated Higgs production processes, showing that they can be encapsulated in four real "high-energy primary" parameters. We assess the reach on these parameters at the LHC and at future hadronic colliders, focusing in particular on the fully leptonic $WZ$ channel that appears particularly promising. The reach is found to be superior to existing constraints by one order of magnitude, providing a test of the SM electroweak sector at the per-mille level, in competition with LEP bounds. Unlike LHC Run-1 bounds, which only apply to new physics effects that are much larger than the SM in the high-energy tail of the distributions, the probe we study applies to a wider class of new physics scenarios where such large departures are not expected.