Analysis of Higgs Physics at the CLIC Electron-Positron Linear Collider
The paper "Higgs Physics at the CLIC Electron-Positron Linear Collider" presents a detailed investigation into the potential of the Compact Linear Collider (CLIC) for Higgs boson studies. CLIC is proposed as a high-energy electron-positron linear collider, which can reach center-of-mass energies up to 3 TeV, enabling precise measurements and exploration of new physics beyond the current Standard Model (SM). The paper is conducted in the context of operating CLIC in three energy stages: 350 GeV, 1.4 TeV, and 3 TeV.
The first stage, at 350 GeV, emphasizes the investigation of the Higgsstrahlung process (e⁺e⁻ → ZH) and the vector boson fusion processes (WW and ZZ fusion), crucial for measuring the couplings of the Higgs boson in a model-independent manner. Particularly significant are the measurements of the Higgs production cross section and total decay width, ν₁, through the recoil mass technique in the ZH production process. The expected precision for the Higgs boson mass is Δm_H = 110 MeV and the coupling to the Z boson, g_{HZZ} = 0.8%, a notable precision reflecting the collider's capabilities at this energy.
At higher energy stages, the focus shifts to WW-fusion, which becomes the dominant production mechanism, particularly at the TeV scale. The operation at 1.4 TeV and 3 TeV significantly enhances the statistics for measurements of rare decays and processes involving the top Yukawa coupling and the Higgs self-coupling. Noteworthy is the precision determination of the top Yukawa coupling in the process e⁺e⁻ → tt̄H and the ability to probe the Higgs self-coupling λ in double Higgs production, a process directly linked to the Higgs potential itself, attainable at 3 TeV.
The paper meticulously evaluates the experimental challenges, including background suppression and the necessity of advanced detector technologies to withstand the beam-induced backgrounds, which are particularly pronounced at higher energies. CLIC's unique ability to polarize electron beams also plays a critical role, allowing for enhanced cross sections in specific channels, as demonstrated in the analyses presented.
From a global perspective, when combined with the LHC data, CLIC's precision measurements will be instrumental in probing the Higgs sector for deviations from the SM predictions. Possible BSM scenarios such as those involving additional Higgs bosons or anomalous couplings could be exposed through these precise tests. The ultimate goal of extending our understanding of the Higgs, potentially unveiling new physics or providing constraints on effective field theories, is underscored throughout the analysis.
In conclusion, the comprehensive capabilities of CLIC as outlined in the paper advocate for its role in the post-LHC era of particle physics. The potential to explore uncharted territories of the Higgs sector and beyond constitutes a compelling case for the development and realization of this advanced colliding facility. Future research and technological advancements will undoubtedly complement the preliminary findings in this paper, furthering CLIC's promise as a facilitator of discovery at the frontiers of theoretical and experimental high-energy physics.