Anomalous Higgs-top Coupling Pollution on Triple Higgs Coupling Extraction at Future High-Luminosity Electron-Positron Collider

TL;DR

This paper investigates how anomalous Higgs-top couplings can interfere with the precise measurement of the Higgs triple coupling at future electron-positron colliders, highlighting energy-dependent pollution effects and potential CP violation signals.

Contribution

It quantifies the impact of Higgs-top anomalous couplings on Higgs triple coupling extraction and explores CP violation measurement via forward-backward asymmetry at future colliders.

Findings

Pollution from Higgs-top coupling is small at 240 GeV but significant at higher energies.

Forward-backward asymmetry can reach 0.7%, comparable to cross section measurement precision.

Energy-dependent effects must be considered in Higgs coupling measurements.

Abstract

One of the most challenging tasks for future high-luminosity electron-positron colliders is to extract Higgs triple coupling. It was proposed that this can be carried out via the precisely measuring the cross section of ZH associated production up to $0.4\%$. In this paper, we example the possible heavy pollution from Higgs-top anomalous coupling. Our numerical results show that the pollution is small for $\sqrt{s}_{e^+e^-}= 240 GeV$. However for the higher energy collider, pollution is sizable, which should be taken into account. We further explored the possibility to measure CP-violated Higgs top coupling, via the forward-backward asymmetry $A_{FB}$ for the process $e^+e^- \rightarrow ZH$. The asymmetry can reach $0.7\%$ which is comparable to the precision of cross section measurement.