# EFT triangles in the same-sign $WW$ scattering process at the HL-LHC and HE-LHC

## TL;DR

This paper assesses the potential of EFT in detecting new physics via same-sign WW scattering at HL-LHC and HE-LHC, finding limited improvement in discovery reach at higher energies.

## Contribution

It evaluates the applicability of dimension-8 EFT operators in same-sign WW scattering at 14 TeV and 27 TeV, highlighting the limited gain in discovery potential with increased energy.

## Key findings

- Discovery regions shift to lower Wilson coefficients at higher energy.
- Overall discovery potential does not significantly improve at 27 TeV.
- EFT approach remains challenging for this process at high energies.

## Abstract

We investigate the Beyond Standard Model discovery potential in the framework of the Effective Field Theory (EFT) for the same-sign $WW$ scattering process in purely leptonic $W$ decay modes at the High-Luminosity and High-Energy phases of the Large Hadron Collider (LHC). The goal of this paper is to examine the applicability of the EFT approach, with one dimension-8 operator varied at a time, to describe a hypothetical new physics signal in the $WWWW$ quartic coupling. In the considered process there is no experimental handle on the $WW$ invariant mass, and it has previously been shown that the discovery potential at 14 TeV is rather slim. In this paper we report the results calculated for a 27 TeV machine and compare them with the discovery potential obtained at 14 TeV. We find that while the respective discovery regions shift to lower values of the Wilson coefficients, the overall discovery potential of this procedure does not get significantly larger with a higher beam energy.