Abstract
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 240 GeV, deliver an integrated luminosity of 5.6 ab−1, and produce one million Higgs bosons according to the CEPC Conceptual Design Report (CDR). Combining measurements of the ℓ+ℓ−H, \( \nu \overline{\nu}H \), and \( q\overline{q}H \) channels, we conclude that the signal strength of \( H\to b\overline{b}/c\overline{c}/ gg \) can be measured with a relative accuracy (relative statistical uncertainty only) of 0.27%/4.03%/1.56%. Extrapolating to the recently released TDR operating parameters corresponding to the integrated luminosity of 20 ab−1, the relative accuracy of \( H\to b\overline{b}/c\overline{c}/ gg \) signal strength is 0.14%/2.13%/0.82% (relative statistical uncertainty only). We analyze the dependence of the expected accuracies on the critical detector performances: Color Singlet Identification (CSI) for the \( q\overline{q}H \) channel and flavor tagging for both \( \nu \overline{\nu}H \) and \( q\overline{q}H \) channels. Compared to the baseline CEPC detector performance, ideal flavor tagging can increase the \( H\to b\overline{b}/c\overline{c}/ gg \) signal strength accuracy by 2%/63%/13% in the \( \nu \overline{\nu}H \) channel and 35%/122%/181% in the \( q\overline{q}H \) channel. A strong dependence between the CSI performance and anticipated accuracies in \( q\overline{q}H \) channel is identified. The relevant systematic uncertainties are also discussed in this paper.
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Zhu, Y., Cui, H. & Ruan, M. The Higgs→ \( b\overline{b} \), \( c\overline{c} \), gg measurement at CEPC. J. High Energ. Phys. 2022, 100 (2022). https://doi.org/10.1007/JHEP11(2022)100
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DOI: https://doi.org/10.1007/JHEP11(2022)100