clic

Compact Linear Collider (CLIC) is a proposed high-energy electron-positron linear collider being studied at CERN. The project envisions a staged program to reach centre-of-mass energies from a first stage of about 380 GeV to later stages at around 1.5 TeV and 3 TeV, enabling precision measurements of the Higgs boson, the top quark, and potential new phenomena in a clean experimental environment.

CLIC uses a novel two-beam acceleration scheme in which a high-intensity, low-energy drive beam runs parallel to the main beam. The drive beam is decelerated in power extraction structures to generate radiofrequency power, which then accelerates the main beam in normal-conducting X-band accelerating structures, achieving gradients around 100 MV/m. This approach allows achieving multi-TeV energies within a relatively compact footprint compared with single-stage designs.

The accelerator is linear to avoid energy loss from synchrotron radiation, and its staged energies are chosen to optimize physics goals and cost. The physics program focuses on precision Higgs measurements, top-quark studies near threshold, and searches for signs of new physics beyond the Standard Model, benefiting from the clean e+e− collision environment.

As a design study, CLIC has undergone several international reviews and design reports but has not yet progressed to construction. It competes with other future lepton collider concepts, notably the ILC, which uses different superconducting RF technology. Prospects for CLIC depend on funding, site decisions, and ongoing R&D on high-gradient X-band structures and beam stability.