About flat telescopic optics for the future operation of the LHC

This report discusses and motivates the possible deployment of flat collision optics for the future operation of the LHC. Performance reach estimates are presented, showing a possible improvement of the peak luminosity by 20 % at constant beam parameters in comparison with round optics, and a virtual luminosity reaching 1.0 × 10$^{35}$ cm$^{−2}$$_{s}$$^{−1}$ assuming the availability, inject-ability and ramp-ability up to 7.0 TeV of the full LIU beam by the end of Run III. These estimates are supported by a certain number of simulation results, including beam-beam effects, and operational aspects based on the first LHC machine development session which took place with probe beams and flat optics in 2017. The main expected optics limitations, together with possible mitigation measures, are also analyzed in details.}