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

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 ${\sqrt{s}}_{e^{+}{e}^{-}}=240GeV$. 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 $e^{+}{e}^{-}\to ZH$. The asymmetry can reach $0.7\%$ which is comparable to the precision of cross section measurement.

Comments: 10 pages, 6 figures, discussions and references added, published in Phys. Rev. D