Strategy and issues for the LHC upgrades and fair, including longer-term prospects

This report discusses the time line, goals and key ingredients for the next ten years of LHC operation, including injector upgrade, for the following High Luminosity LHC (HL-LHC), and for the FAIR project. Results from pertinent EuCARD-WP4 workshops on optics, space charge, crab cavities, crystal collimation, and electron cloud are summarized in this context. A Large Hadron electron Collider, LHeC, would be an additional upgrade, further expanding the physics scope of the LHC, to eventually include both ep and γγ Higgs factories (LHeC-HF and SAPPHiRE). Results from relevant topical WP4 workshops are highlighted. The development of magnet and cable technology based on Nb$_{3}$Sn, and HTS, for the HL-LHC prepares the ground for a future higher-energy hadron collider, either in the LHC tunnel, “HELHC” (33 TeV c.m.), or in a new 80- or 100-km tunnel, “VHE-LHC” (100 TeV c.m.). A large new tunnel could also host an ultimate highest-precision e+e- Higgs factory collider, “TLEP,” exhibiting many synergies and sharing components with VHE-LHC and LHeC/SAPPHiRE. As a possible back-up option, “LEP3” would be an e+e- Higgs factory in the LHC tunnel. WP4 AccNet organized the first ever workshops on HE-LHC, VHE-LHC, LEP3, TLEP, and SAPPHiRE, respectively. FAIR is advancing the development of fast cycling superconducting magnets. Such magnets, as well as alternative designs based on the transmission-line concept, are of interest for the injector ring of the VHE-LHC or HE-LHC. Putting the various elements together, EuCARD-AccNet has developed a coherent vision for future accelerator-based high-energy physics in form of a sequence of circular high performance colliders leading up to the 100-TeV energy scale and extending over most of the 21st century.