Interference effects on Higgs mass measurement in $e^+e^-\to H(\gamma\gamma) Z$ at CEPC

TL;DR

This paper investigates how interference effects impact the precision measurement of the Higgs mass via the diphoton decay mode at the CEPC, revealing mass shifts up to 50 MeV depending on experimental resolution.

Contribution

It provides a detailed analysis of signal-background interference effects on Higgs mass measurement at future $e^+e^-$ colliders, highlighting the significance of these effects for precision physics.

Findings

Mass shifts range from 20 to 50 MeV due to interference effects.

Mass shifts increase with poorer experimental mass resolution.

Interference effects are crucial for accurate Higgs mass determination.

Abstract

A high luminosity Circular Electron Positron Collider (CEPC) as a Higgs Factory will be helpful to the precision measurement of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in the associated Z boson production at the future $e^+e^-$ colliders at energy $246 {\rm GeV}$. The mass shifts go up from about $20 {\rm MeV}$ to $50 {\rm MeV}$ for the experimental mass resolution ranging from $0.8 {\rm GeV}$ to $2 {\rm GeV}$.