[Paper Review] Physics at the CLIC e+e- Linear Collider -- Input to the Snowmass process 2013

H. Abramowicz, A. C. Abusleme Hoffman+121 more|arXiv (Cornell University)|Jul 19, 2013

Distributed and Parallel Computing Systems8 references74 citations

TL;DR

This paper presents the physics potential of the CLIC e+e− linear collider, proposing a staged 3-TeV collider with high luminosity to enable precision measurements of the Higgs boson, top quark, and electroweak interactions, while probing new physics beyond the Standard Model. It demonstrates that CLIC can measure Higgs couplings at ~2% precision and the trilinear self-coupling at 10%, with sensitivity to new physics up to 20–30 TeV.

ABSTRACT

This paper summarizes the physics potential of the CLIC high-energy e+e- linear collider. It provides input to the Snowmass 2013 process for the energy-frontier working groups on The Higgs Boson (HE1), Precision Study of Electroweak Interactions (HE2), Fully Understanding the Top Quark (HE3), as well as The Path Beyond the Standard Model -- New Particles, Forces, and Dimensions (HE4). It is accompanied by a paper describing the CLIC accelerator study, submitted to the Frontier Capabilities group of the Snowmass process.

Motivation & Objective

• To assess the physics reach of the CLIC e+e− linear collider for the 2013 Snowmass process, focusing on energy-frontier physics.
• To evaluate the feasibility and physics potential of a staged CLIC implementation at 350 GeV, 1.4 TeV, and 3.0 TeV center-of-mass energies.
• To demonstrate CLIC's capability to measure Higgs boson properties, top quark couplings, and electroweak parameters with sub-2% precision.
• To explore sensitivity to new physics, including supersymmetry and composite Higgs models, up to scales of 20–30 TeV.
• To provide input for future accelerator development by showing CLIC's complementary role to the HL-LHC in probing the electroweak scale.

Proposed method

• Utilizes full detector simulation and event reconstruction, including pile-up from γγ→hadrons, to model physics performance.
• Employs a staged energy operation strategy: 350 GeV for Higgs and top quark precision, followed by 1.4 TeV and 3.0 TeV for high-precision and new physics searches.
• Applies precision measurements of fermion production asymmetries and W-boson mass to determine sin²θefff at various energy stages.
• Performs simulations of triple and quartic gauge boson vertex corrections in ep→W+W− processes to probe anomalous couplings.
• Uses form-factor suppression/enhancement searches in total ep→f¯f cross sections at high energy and with polarized beams.
• Analyzes sensitivity to CP-even and CP-odd anomalous couplings via real parts of gauge boson couplings, with energy scaling studies.

Experimental results

Research questions

• RQ1 Can CLIC achieve sub-2% precision in measuring Higgs boson couplings and total decay width at 3 TeV?
• RQ2 What is the sensitivity of CLIC to the Higgs trilinear self-coupling λ, and can it distinguish it from the Standard Model prediction?
• RQ3 To what extent can CLIC probe new physics beyond the Standard Model, such as supersymmetric particles or composite Higgs states?
• RQ4 How do beam polarization and energy staging improve the precision of electroweak measurements and new physics searches?
• RQ5 What is the reach of CLIC in probing new gauge bosons (Z′) and Higgs compositeness up to high energy scales?

Key findings

• CLIC at √s = 3.0 TeV can measure Higgs couplings with ~2% precision, significantly exceeding the HL-LHC's reach.
• The Higgs trilinear self-coupling λ can be measured at the 10% level, enabling distinction between a Standard Model Higgs and extended theories.
• Sensitivity to anomalous W W γ and W W Z couplings improves with energy, with Re(Δg₁ᴸ) reaching 0.93×10⁻³ at 3 TeV.
• CLIC can measure gaugino, slepton, and heavy Higgs masses with ~1% precision up to ~1.5 TeV kinematic limits.
• Models with Z′ bosons and Higgs compositeness can be probed up to scales of ~20 TeV and ~30 TeV, respectively.
• The precision electroweak program enables determination of sin²θefff and W-boson mass with high accuracy across all energy stages.