Future Of The Large Hadron Collider, The: A Super-accelerator With Multiple Possible Lives

The Large Hadron Collider (LHC) is the highest energy collider ever built. It resides near Geneva in a tunnel 3.8m wide, with a circumference of 26.7km, which was excavated in 1983–1988 to initially house the electron-positron collider LEP. The LHC was approved in 1995, and it took until 2010 for reliable operation. By now, a larger set of larger integrated luminosities have been accumulated for physics analyses in the four collider experiments: ATLAS, CMS, LHCb and ALICE. The LHC operates with an extended cryogenic plant, using a multi-stage injection system comprising the PS and SPS accelerators (still in use for particle physics experiments at lower energies). The beams are guided by 1232 superconducting high field dipole magnets. Intense works are underway in preparation of the High Luminosity LHC, aimed at upgrading the LHC and detectors for collecting ten times more luminosity, and extending the collider life to the early 2040's. So far, the (HL-)LHC project represents a cumulation of around one hundred thousand person-years of innovative work by technicians, engineers, and physicists from all over the world; probably the largest scientific effort ever in the history of humanity. The book is driven by the realisation of the unique value of this accelerator complex and by the recognition of the status of high energy physics, described by a Standard Model — which still leaves too many questions unanswered to be the appropriate theory of elementary particles and their interactions. Following the Introduction are: three chapters which focus on the initial decade of operation, leading to the celebrated discovery of the Higgs Boson, on the techniques and physics of the luminosity upgrade, and finally on major options - of using the LHC in a concurrent, power economic, electron-hadron scattering mode, when upgraded to higher energies or eventually as an injector for the next big machine. The various technical and physics chapters, provided by 61 authors, characterise the fascinating opportunities the LHC offers for the next two decades ahead (possibly longer), with the goal to substantially advance our understanding of nature.

Born in 1964 in Hamburg, Germany, Dr Oliver Brüning is a senior scientist at CERN. He is specialized in accelerator physics and has worked on several flagship accelerator projects since 1991. His involvement in accelerator projects is ranging from non-linear beam dynamics studies and the commissioning of the HERA electron-proton collider at DESY, to the LEP-II upgrade and the LHC design and commissioning at CERN. He was one of the initial LHC Commissioning coordinators from 2008 until 2013 and has led the CERN Accelerator Beam Physics group from 2005 until 2015. Since 2010 he has been the deputy project leader of the HL-LHC upgrade and is leading the project since 2021.

Max Klein has worked on theory, detectors, data analysis and coordination of particle physics experiments at several accelerators at CERN (Geneva, Switzerland) and at DESY (Hamburg, Germany). As a postdoc, he spent several years at JINR (Dubna, Soviet Union).

Max was initially employed by the Institute for High Energy Physics at Zeuthen near Berlin, which is now a part of DESY. He has been a Professor at the University of Liverpool since 2006, Emeritus since 2022. For many years, Max has been coordinating the development of the Large Hadron electron Collider and the FCC-eh projects, options for luminous, energy frontier electron-hadron scattering experiments at CERN.

Max served as Spokesperson of the H1 Collaboration at the electron-proton collider HERA. Recently, he chaired the Collaboration Board of the ATLAS experiment at CERN as well as an accelerator expert panel laying out a European Roadmap for the Research and Development on Energy Recovery Linacs (ERL). He currently is the Spokesperson of the high power ERL facility PERLE, which is being built at Irene Joliot Curie Laboratory, Orsay (France).

His contributions to Particle Physics has earned him the Max-Born-Prize of the Institute of Physics and the German Physics Society.

Lucio Rossi is full professor of Experimental Physics at the Physics department of the University of Milano. He was at CERN from 2001 to 2020, where he led the LHC superconducting magnets construction and then he proposed and led the High Luminosity LHC project. After retirement from CERN, at University and INFN-Milano, he is pursuing new advanced technologies for cancer therapy with heavy ion particles (a superconducting gantry) and for FCC-hh and the Muon Collider projects for the post-HiLumi LHC era. He is also co-leader of IRIS, a large program in Italy of the Next Generation Europe, with the goal of developing new research infrastructures in Milano, Genova, Frascati, Napoli, Salerno and Lecce, and of design and building two new lag demonstrator: a 1 GW Superconducting line (with MgB2) for green energy and an energy saving 10 T magnet with HTS conductor.

He has authored more than 200 publications in international journals and reviews and he is active in public outreach on science and large projects, developing themes like the relation between science and technology, "certainty and truth." He has recently published an autobiographical book: Lucio Rossi, <a href="http://www.bietti.it/negozio/la-conoscenza-e-unavventura/" target="blank">La conoscenza è un'avventura</a>, edizioni Bietti, Milano, 2022.

Paolo Spagnolo is research director at the INFN, Pisa, Italy. He is member of CMS and in the Italian review board of the LHCb Experiment and the LHC Computing. He is also the author and co-author of about 1350 papers with a h-index=184. He is also a co-founder of the CERN spin-off Planetwatch.''

Paolo has gathered many years of expertise in Particle Physics, data analysis and detector development, from his time working at CERN, where he was Research Fellow and Scientific Associate within the ALEPH and the CMS collaborations.