PARAMETER SPACE FOR THE LHC LUMINOSITY UPGRADE

We review the parameter space for the high-luminosity upgrade of the LHC (HL-LHC). Starting from the luminosity targets and the primary limitations, e.g., event pile up, turnaround time, injector limits, and intrabeam scattering, we determine compatible beam parameters such as the beam intensity, bunch spacing, transverse and longitudinal emittances, bunch length, and IP beta functions required to meet the HL-LHC goals. Possible HL-LHC parameter sets together with their expected performance reach are presented for comparison and discussion. TARGET PERFORMANCE The High-Luminosity Large Hadron Collider (HL-LHC) represents an extensive upgrade of the LHC accelerator and detectors which is planned to be implemented in stages, with the final installations foreseen during a 2-year shutdown in 2022/23. The HL-LHC project aims at a total integrated luminosity of approximately 3000 fb −1 over the entire lifetime of the HL-LHC, including about 400 fb −1 accumulated in the lower-luminosity running period through 2021. Assuming an exploitation period of ca. 10 years for the HL-LHC alone, this goal implies an annual integrated HL-LHC luminosity of approximately 200 fb −1 to 300 fb −1 per year, e.g. from 2024 to 2033. In the following we assume an annual target luminosity of 250 fb −1 .