# Same-sign WW Scattering in the HEFT: Discoverability vs. EFT Validity

## TL;DR

This paper examines same-sign WW scattering within the HEFT framework to identify regions where new physics signals could be detected at HL-LHC while ensuring EFT validity, and compares these with SMEFT results.

## Contribution

It clarifies the correct application of HEFT in vector boson scattering and maps out parameter regions for potential discovery consistent with EFT validity.

## Key findings

- Regions with >5σ significance for new physics at HL-LHC identified
- Bounds on the  parameter in the composite Higgs model established
- Comparison with SMEFT analysis and literature discussed

## Abstract

Vector boson scatterings are fundamental processes to shed light on the nature of the electroweak symmetry breaking mechanism. Deviations from the Standard Model predictions on the corresponding observables can be interpreted in terms of effective field theories, that however undergo consistency conditions. In this paper, the same-sign W W scattering is considered within the HEFT context and the correct usage of the effective field theory approach is discussed. Regions of the parameters space are identified where a signal of new physics could be measured at HL-LHC with a significance of more than 5$\sigma$ and the effective field theory description is consistently adopted. These results are then translated into bounds on the $\xi$ parameter in the composite Higgs scenario. The discussion on the agreement with previous literature and the comparison with the equivalent analysis in the SMEFT case are also included.