Interference effects on Higgs mass measurement in e+ e−→ H(γγ) Z at CEPC**Supported by National Natural Science Foundation of China (11375021, 11447018), New Century Excellent Talents in University (NCET) (NCET-13-0030), Major State Basic Research Development Program of China (2015CB856701), Fundamental Research Funds for Central Universities, and Education Ministry of LiaoNing Province.

Guang-Zhi Xu,Yu-Jie Zhang,Gang Li,Kui-Yong Liu,Yi-Jie Li

doi:10.1088/1674-1137/40/3/033101

Abstract

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

Highlights

The ATLAS and CMS collaborations at the Large Hadron Collider (LHC) announced the amazing discovery of a new particle with a mass of around 125GeV in July 2012[1, 2] and it’s properties are well compatible with the Standard Model (SM) Higgs boson[3] but leave the room for new physics
For future Higgs factories, the e+e− → Z∗ → Z + H(γγ) process will be an excellent channel for precision measurement
The interference effects for the Higgs mass in the diphoton decay mode at the hadron colliders have been discussed based on the theoretical aspects

Summary

Introduction

The ATLAS and CMS collaborations at the Large Hadron Collider (LHC) announced the amazing discovery of a new particle with a mass of around 125GeV in July 2012[1, 2] and it’s properties are well compatible with the Standard Model (SM) Higgs boson[3] but leave the room for new physics. The interference effects for the Higgs mass in the diphoton decay mode at the hadron colliders have been discussed based on the theoretical aspects. This work will focuse on the interference effect of the Higgs mass through diphoton decay mode in Higgsbremsstrahlung process at the future e+e− colliders CEPC (Several discussions at CEPC refer to Refs.[23,24,25,26]). This interference effect with fixed polarisation at the initial state has been considered in Ref.[27], and a mass shift in range of O(100MeV) is found. The interference effect but with unpolarized initial state will be revisited

Calculations and analysis

Findings

Summary