Accurately measuring the properties of the Higgs boson is one of the core physics objectives of the Circular Electron Positron Collider (CEPC). As a Higgs factory, the CEPC is expected to operate at a centre-of-mass energy of 240GeV, deliver an integrated luminosity of 5.6ab−1, and produce one million Higgs bosons according to the CEPC Conceptual Design Report (CDR). Combining measurements of the ℓ+ℓ−H, ννˉH, and qqˉH channels, we conclude that the signal strength of H→bbˉ/ccˉ/gg can be measured with a relative accuracy (statistic uncertainty only) of 0.27\%/4.03\%/1.56\%. Extrapolating to the recently released TDR operating parameters corresponding to the integrated luminosity of 20ab−1, the relative accuracy of H→bbˉ/ccˉ/gg signal strength is 0.14\%/2.13\%/0.82\%. We analyze the dependence of the expected accuracies on the critical detector performances: Color Singlet Identification (CSI) for the qqˉH channel and flavor tagging for both ννˉH and qqˉH channels. We observe that compared to the baseline CEPC detector performance, ideal flavor tagging increases the H→bbˉ/ccˉ/gg signal strength accuracy by 2\%/63\%/13\% in the ννˉH channel and 35\%/122\%/181\% in the qqˉH channel. In addition, better performance of CSI can significantly improve the anticipated accuracy of signal strength. The relevant systematics are also discussed in this paper.
@article{arxiv.2203.01469,
title = {The $Higgs\to b\bar{b}, c\bar{c}, gg$ measurement at CEPC},
author = {Yongfeng Zhu and Hanhua Cui and Manqi Ruan},
journal= {arXiv preprint arXiv:2203.01469},
year = {2022}
}