Associated Higgs production in lepton-photon collisions at FCC-ee

Abstract

Following the HL-LHC era, proposed lepton colliders highlight the need to study various important Higgs boson production mechanisms to precisely probe the Standard Model Higgs sector. We propose a novel mechanism $e^\pm γ\rightarrow {\bar ν}_e (ν_e) H W^\pm$, which can be useful to study Higgs boson properties. This channel is relatively free from the background and can be used to measure the Higgs boson properties, in particular $WWH$ coupling. We examine the viability of this production mechanism. We show that the process can be observed at the planned FCC-ee with the center-of-mass energy of 365 GeV. At the center-of-mass energy of 500 GeV, the process can be observed within a few months of the operation. We use an in-house Monte Carlo event generator that simultaneously incorporates the photon distribution and electron/positron distribution. Our work is also a step towards realistic simulations of lepton- and photon-initiated processes at lepton colliders.

Figures (6)

• Figure 1: Feynman diagrams for the process $e^-\gamma\rightarrow \nu_e H W^-$.
• Figure 2: Variation of total cross section as a function of center-of-mass energy of the FCC-ee.
• Figure 3: Distribution of two $b$-jets invariant mass $m_{bb}$.
• Figure 4: Distribution of $\eta$ of subleading $b$-jet.
• Figure 5: Significance as a function of integrated luminosity (bottom x-axis) and as a function of year (top x-axis) for $E_{\rm CM}=$ 365 GeV FCC-ee. The number of signal (solid) and background (dashed) events is also plotted in blue and can be read from the right y-axis. A 5$\sigma$ significance is achievable in 2 years.