Mixed electroweak-QCD corrections to $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}H$ at CEPC with finite-width effect

Abstract

The associated production of Higgs boson with a muon pair, $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}H$, is one of the golden channels to pin down the properties of the Higgs boson in the prospective Higgs factories exemplified by \textsf{CEPC}. The projected accuracy of the corresponding cross section measurement is about per cent level at CEPC. In this work, we investigate both $\mathcal{O}(\alpha )$ weak correction and the $\mathcal{O}(\alpha {\alpha }_s)$ mixed electroweak-QCD corrections for this channel, appropriately taking into account the effect of finite $Z^0$ width. The ${\mu }^{+}{\mu }^{-}$ invariant mass spectrum is also predicted. The mixed electroweak-QCD correction turns out to reach 1.5\% of the Born-order result, and thereby must be included in future confrontation with the data. We also observe that, after including higher-order corrections, the simplified prediction for the integrated cross section employing the narrow-width-approximation may deviate from our full result by a few per cents.

Comments: v2, 15 pages, 5 figures, 3 tables. Typos corrected, references added, the version to appear in Chinese Physics C