Differential measurements of $\bar{t}tZ$ and $\bar{t}t\bar{t}t$ at large $Q^2$ at FCC-hh

TL;DR

This study explores differential measurements of top-quark related processes at FCC-hh, emphasizing high-energy regimes to enhance sensitivity to potential new physics within an Effective Field Theory framework.

Contribution

It provides detailed analysis of top-quark production processes at high energies, including improved lepton isolation techniques and measurable distributions up to multi-TeV scales.

Findings

Transverse momentum distribution of Z bosons measurable up to 2 TeV with 20% precision.

Four-top scalar transverse momentum reaches 3.5 TeV with 35% precision.

Redefining lepton isolation improves signal yield by 50%.

Abstract

This contribution presents studies of differential top-quark measurements at the Future Circular Collider in its proton-proton stage (FCC-hh). The analyses target the leptonic final states of the $\bar{t}tZ$ and $\bar{t}t\bar{t}t$ production processes. Particular focus is given to the high-$Q^2$ regime, where sensitivity to new physics, as encoded in an Effective Field Theory framework, is enhanced. The dataset corresponds to an integrated luminosity of 30 $\text{ab}^{-1}$ at $\sqrt{s} = 84$ TeV. The reconstructed transverse momentum $\text{p}_\text{T}(Z_{\ell\ell})$ distribution is shown to be measurable up to approximately 2 TeV with a precision of 20% in the high energy region ($\text{p}_\text{T}(Z_{\ell\ell})$ >1.8 TeV). The scalar transverse momentum $\text{H}_\text{T}$ of the four-top production reaches 3.5 TeV with a precision of 35%. Additionally, a dedicated study of the lepton reconstruction efficiency shows that redefining the isolation variable to account for the highly boosted objects at FCC-hh improves the total signal yield in $\bar{t}tZ$ by a factor of 1.5.