The W and Z scattering as a probe of physics beyond the Standard Model: Effective Field Theory approach

TL;DR

This paper explores vector boson scattering at the LHC using Effective Field Theory to identify potential signs of physics beyond the Standard Model, comparing SMEFT and HEFT frameworks, and assessing energy dependence of discovery regions.

Contribution

It introduces a novel method for determining discovery regions of EFT models in vector boson scattering and compares SMEFT and HEFT signatures at high energies.

Findings

Discovery regions are non-empty across EFT models.

Differences in SMEFT and HEFT signatures can help distinguish hypotheses.

Higher collision energies expand the discovery regions.

Abstract

In this work the vector boson scattering process is investigated through the reaction $pp\rightarrow 2 \mathrm{jets} + W^\ast W^\ast \rightarrow 2 \mathrm{jets} + l\nu_l l'\nu_l'$, where $W^\ast$ denote in general off-shell $W^+$, in the EFT approach with the HL-LHC and HE-LHC experiments in mind. We have investigated the discovery potential of certain classes of the EFT "models" of both the SMEFT and HEFT bases with the particular emphasis on using the EFT "models" in their region of validity. A novel method has been proposed for determining the discovery regions of physics beyond the SM, described by the EFT "models". Independent of the basis chosen, the discovery regions are found to be non-empty. We then compare differences in experimental signatures between SMEFT and HEFT, which is an important step for distinguishing between the two hypotheses in the future data. Finally, we investigated what the effect on the discovery regions is when increasing the $pp$ collision energy.