The Gamma Factory path to high luminosity LHC with laser-cooled isoscalar ion beams

The seminar will be focussed on one of the case studies of the Gamma Factory initiative ( https://arxiv.org/abs/1511.07794 ) — on a proposal of a new operation scheme of beams in the CERN accelerator complex. Its goal is to extend the scope and precision of the LHC-based research by complementing the proton--proton collision programme with the high-luminosity, nucleus--nucleus one. Its numerous physics highlights include studies of the exclusive Higgs-boson production in photon--photon collisions and precision measurements of the electroweak (EW) parameters.

There are two principal ways to increase the LHC luminosity which do not require an upgrade of the CERN injectors: (1) modification of the beam-collision optics, and (2) reduction of the transverse emittance of the colliding beams. The former scheme is employed by the ongoing high-luminosity (HL-LHC) project. The latter one, applicable only to ion beams, will be discussed in this seminar. It is based on laser cooling of bunches of partially stripped ions. The expected nucleon—nucleon luminosity of L_{NN}= 4.2 x 10^{34} s^{-1}cm^{-2} is comparable to the levelled luminosity for the HL-LHC proton—proton collisions, but with reduced pile-up background. The scheme proposed in this paper, if validated by the future Gamma Factory proof-of-principle experiment, could be implemented at CERN with minor infrastructure investments