Measurement of the $H$ to $ZZ$ branching fraction at a 350 GeV and 3 TeV CLIC

In this paper we investigate the prospects for measuring the branching fraction of the Standard Model Higgs boson decay into a pair of $Z$ bosons at the future Compact Linear Collider (CLIC) at 350 GeV and 3 TeV center-of-mass energies. Studies are performed using a detailed simulation of the detector for CLIC, taking into consideration all relevant physics and beam-induced background processes. It is shown that the product of the Higgs production cross section and the branching fraction $\mathrm{BR}(H\to Z{Z}^{*})$ can be measured with a relative statistical uncertainty of 20% (3.0%) at a center-of-mass energy of 350 GeV (3 TeV) using semileptonic final states, assuming an integrated luminosity of $1{\mathrm{ab}}^{-1}$ ($5{\mathrm{ab}}^{-1}$).

Figure 1

Unpolarized cross sections as a function of center-of-mass energy for the main Higgs production processes at an $e^{+}{e}^{-}$ collider, assuming a Higgs boson mass of 126 GeV [2].

Figure 2

Energy of the reconstructed signal leptons (solid line) and other reconstructed PFO objects (dashed line) in signal events, at 3 TeV center-of-mass energy.

Figure 3

Calorimeter energy ratio $R_{\mathrm{CAL}}$ [Eq. (1)] of reconstructed electrons and muons (solid line) and other reconstructed particles (dashed line), for signal at 3 TeV center-of-mass energy.

Figure 4

Cone energy as a function of reconstructed lepton energy (a) at 350 GeV and (b) at 3 TeV center-of-mass energy. The red line represents the polynomial distribution from Eq. (2), separating the isolated lepton from other particles in an event.

Figure 5

Stacked histograms of the Higgs mass distributions after the preselection phase at (a) 350 GeV and (b) 3 TeV.

Figure 6

Stacked histograms of the Higgs mass distributions after MVA, at (a) 350 GeV and (b) 3 TeV center-of-mass energies.