The FCCs

The Future Circular Colliders (FCCs) address some of the most fundamental open issues in particle physics

Following the discovery of the Higgs boson by ATLAS and CMS at the LHC in 2012, coupled with the absence of other phenomena, the particle physics panorama has become, surprisingly perhaps, very open. While the Standard model could appear to be complete and the vacuum stable all the way to the Plank scale, several undeniable observations tell us that there is more to the story. The nature of dark matter, the origin of the baryon asymmetry in the universe, the mysteries lying behind the very small neutrino masses, are telling us to keep looking for answers, which  require new phenomena. Are those to be found at higher energies, or have they escaped detection because of very small couplings?

The design study of the accelerators that would fit in a new 80-100 km “circular” tunnel, called the “Future Circular Colliders”, implements the recommendations of the European Strategy document approved by the CERN council in May 2013. It was launched in a kick-off meeting held in University of Geneva on 12-15 February 2014, and aims at a Conceptual Design Report by 2018.

Two colliders in one

Effectively, the FCCs would be two colliders in one: the study comprises a high energy proton-proton collider with a centre-of-mass energy of 100 TeV (FCC-hh), as well as a 90-400 GeV high luminosity e+e-  machine (FCC-ee a.k.a. “TLEP”).  This ambitious complex would also allow the use of heavy ions and e-p collisions.  The 100 TeV proton machine constitutes the ultimate goal while the e+e- machine provides a possible intermediate step. This complex of machines bears promise of the most powerful search for new phenomena, either directly at high energies or in rare processes, or through the most sensitive and precise measurements of the Higgs boson and other Standard model particles. Either way, a sensitivity to a variety of new phenomena at energy scales of 30 to 50 TeV can be achieved.