Speaker
Andrea Dainese
(INFN - Padova (IT))
Description
A five-year international design study called Future Circular Collider (FCC) has been launched by CERN with a kick-off meeting in February 2014. The main goal is a hadron collider with a centre-of-mass energy of the order of 100 TeV for pp collisions in a new 80-100 km tunnel in the Geneva area. The target start of operation would be 2035-40.
Operating such machine with heavy ions is an option that is being considered in the accelerator design studies. It would provide, for example, Pb-Pb and p-Pb collisions at $\sqrt{s_{\rm NN}}=39$ and 63 TeV, respectively, with monthly integrated luminosities of the order of 5-10/nb.
We will present first ideas on the physics opportunities with heavy ions at the FCC.
The Quark-Gluon Plasma (QGP) state produced in Pb-Pb collisions at 39~TeV is expected to have initial temperature and energy density substantially larger than at LHC energy, a stronger flow field and freeze-out volume twice as large. The larger temperature could entail novel features, like changes in the quarkonium spectrum and abundant in-medium production of charm quarks. The latter could determine an increase in the number of degrees of freedom (from 3 to 4 quark flavours).
The larger energy and luminosities will make new, rarer, hard probes available (like top quarks and $Z+Jets$), which could give access to the time-evolution of the medium properties, e.g. of its opacity.
In the sector of small-$x$ and saturation physics, the increase in centre-of-mass energy of a factor seven with respect to the LHC will extend the kinematic coverage in $x$ and $Q^2$, providing, with pA and $\gamma$A (ultra-peripheral collisions), access to the saturation region down to $x< 10^{-6}$ with perturbative probes like heavy quarks and quarkonia.
High-density or collective effects in high-multiplicity pp and pA events could become more dramatic, with the increase of energy and high-multiplicity reach.
Opportunities for electroweak physics studies in UPC gamma-gamma collisions, as well as the impact of heavy-ion data at the FCC for ultra-high energy cosmic-ray physics, will also be summarized.
Author
Andrea Dainese
(INFN - Padova (IT))
Co-authors
Carlos Albert Salgado Lopez
(Universidade de Santiago de Compostela (ES))
Dr
Christof Roland
(Massachusetts Inst. of Technology (US))
David d'Enterria
(CERN)
Marco Van Leeuwen
(University of Utrecht (NL))
Nestor Armesto Perez
(Universidade de Santiago de Compostela (ES))
Dr
Silvia Masciocchi
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
Urs Wiedemann
(CERN)
