• Radiation effects in the LHC experiments: Impact on detector performance and operation
    Vol. 1 (2021)

    Editor: I. Dawson

    This report documents the knowledge and experiences gained by the LHC experiments in running detector systems in radiation environments during 2010–2018, with a focus on the inner detector systems. During this time, the LHC machine has delivered a large fraction of the design luminosity to the experiments and the deleterious effects of radiation on detector operation are being observed and measured. It is timely to review the findings from across the experiments.
    Questions we aim to answer include:

    • Are the detector systems operating and performing as expected?
    • How reliable are the radiation damage models and predictions?
    • How accurate are the Monte Carlo simulation codes?
    • Have there been unexpected effects?
    • What mitigation strategies have been developed?

    A major goal of this report is to provide a reference for future upgrades and for future collider studies, summarizing the experiences and challenges in designing complex detector systems for operation in harsh radiation environments.

  • High-Luminosity Large Hadron Collider (HL-LHC): Technical design report
    Vol. 10 (2020)

    Editors: I. Béjar Alonso, O. Brüning, P. Fessia, M. Lamont, L. Rossi, L. Tavian, M. Zerlauth

    The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total number of collisions) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require new infrastructures (underground and on surface) and over a decade to implement. The new configuration, known as High Luminosity LHC (HL-LHC), relies on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 Tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 100 metre-long high-power superconducting links with negligible energy dissipation, all of which required several years of dedicated R&D effort on a global international level.

    The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of the HL-LHC.

    ISBN 978-92-9083-586-8 (paperback), ISBN 978-92-9083-587-5 (PDF). 

  • A primary electron beam facility at CERN—eSPS: Conceptual design report
    Vol. 8 (2020)

    Editors: Torsten Åkesson and Steinar Stapnes

    The design of a primary electron beam facility at CERN is described. The study has been carried out within the framework of the wider Physics Beyond Colliders study. It re-enables the Super Proton Synchrotron (SPS) as an electron accelerator, and leverages the development invested in Compact Linear Collider (CLIC) technology for its injector and as an accelerator research and development infrastructure. The facility would be relevant for several of the key priorities in the 2020 update of the European Strategy for Particle Physics, such as an electron-positron Higgs factory, accelerator R&D, dark sector physics, and neutrino physics. In addition, it could serve experiments in nuclear physics. The electron beam delivered by this facility would provide access to light dark matter production significantly beyond the targets predicted by a thermal dark matter origin, and for natures of dark matter particles that are not accessible by direct detection experiments. It would also enable electro-nuclear measurements crucial for precise modelling the energy dependence of neutrino-nucleus interactions, which is needed to precisely measure neutrino oscillations as a function of energy. The implementation of the facility is the natural next step in the development of X-band high-gradient acceleration technology, a key technology for compact and cost-effective electron/positron linacs. It would also become the only facility with multi-GeV drive bunches and truly independent electron witness bunches for plasma wakefield acceleration. A second phase capable to deliver positron witness bunches would make it a complete facility for plasma wakefield collider studies.
    The facility would be used for the development and studies of a large number of components and phenomena for a future electron-positron Higgs and electroweak factory as the first stage of a next circular collider at CERN, and its cavities in the SPS would be the same type as foreseen for such a future collider. The operation of the SPS with electrons would train a new generation of CERN staff on circular electron accelerators. The facility could start operation in about five years, and would operate in parallel and without interference with Run 4 of the LHC.

  • Linac4 design report
    Vol. 6 (2020)

    Editor: Maurizio Vretenar

    Linear accelerator 4 (Linac4) is designed to accelerate negative hydrogen ions for injection into the Proton Synchrotron Booster (PSB). It will become the source of proton beams for the Large Hadron Collider (LHC) after the long shutdown in 2019–2020. Linac4 will accelerate H– ions, consisting of a hydrogen atom with an additional electron, to 160 MeV energy and then inject them into the PSB, which is part of the LHC injection chain. The new accelerator comprises an ion source and four types of accelerating structures. The particles are accelerated first to 3 MeV energy by a Radio-Frequency Quadrupole (RFQ), then to 50 MeV by three Drift Tube Linacs (DTL) tanks, then to 100 MeV by seven Cell-Coupled Drift Tube Linac (CCDTL) modules, and finally to 160 MeV by twelve Pi-Mode Structures (PIMS). A chopper line placed between the RFQ and the first DTL tank modulates the linac beam at the PSB injection frequency. Linac4 includes transfer and measurement lines up to the PSB injection, where the ions are stripped of their two electrons to leave only protons. Linac4 is 76 metres long and located 12 metres below ground. The first low-energy beams were produced in 2013 and after the commissioning of all accelerating structures the milestone energy of 160 MeV was reached in 2016. Linac4 will be connected to the PSB during the long shutdown of 2019–20, after which it will replace the 50 MeV Linac2 as source of protons for the LHC. The Linac4 is a key element in the project to increase the luminosity of the LHC during the next decade.

  • LHC fixed target experiments: Report from the LHC Fixed Target Working Group of the CERN Physics Beyond Colliders Forum
    Vol. 4 (2020)

    Corresponding editor:

    Several fixed-target experiments at the LHC are being proposed and actively studied. Splitting of beam halo from the core by means of a bent crystal combined with a second bent crystal after the target has been suggested in order to study magnetic and electric dipole moments of short-lived particles. A similar scheme without the second crystal or other schemes with more conventional solid or gas targets have been proposed to study hadronic matter and the quark-gluon plasma, as well as to provide inputs to cosmic ray physics. Most notably, an upgrade of the existing and already productive LHCb gas target (SMOG), which would make use of a storage cell, has been proposed, designed, and extensively reviewed. The implementation in LHCb of a polarised gas target, based on the storage cell technique, was also discussed, motivated by the nucleon-spin study. The status of these proposals, their technical feasibility and impacts on the LHC machine have been studied in the LHC Fixed Target Working Group of the Physics Beyond Collider forum at CERN. The status and outcome of these studies are presented here.

  • Theory for the FCC-ee: Report on the 11th FCC-ee Workshop, Theory and Experiments, CERN, Geneva, 8–11 January 2019
    Vol. 3 (2020)

    Eds. A. Blondel, J. Gluza, S. Jadach, P. Janot and T. Riemann

    The Future Circular Collider (FCC) at CERN, a proposed 100 km circular facility with several colliders in succession, culminates in a 100 TeV proton–proton collider. It offers a vast new domain of exploration in particle physics, with orders-of-magnitude advances in terms of precision, sensitivity, and energy. The implementation plan published in 2018 foresees, as a first step, an electroweak factory electron–positron collider. This high-luminosity facility, operating at centre-of-mass energies between 90 and 365 GeV, will study the heavy particles of the Standard Model (SM), Z, W, and Higgs bosons, and top quarks with unprecedented accuracy. The physics programme offers great discovery potential: (i) through precision measurements, (ii) through sensitive searches for symmetry violations, forbidden, or extremely rare decays, and (iii) through the search for direct observation of new particles with extremely small couplings. The electroweak factory e+e- collider constitutes a real challenge to the theory and to precision calculations, triggering the need for the development of new mathematical methods and software tools. A first workshop in 2018 focused on the first FCC-ee stage, the Tera-Z, and confronted the theoretical status of precision Standard Model calculations on the Z boson resonance to the experimental demands. The second workshop, in January 2019, extended the scope to the next stages, with the production of W bosons (FCC-ee-W), the Higgs boson (FCC-ee-H), and top quarks (FCC-ee-tt). In particular, the theoretical precision in the determination of the crucial input parameters, αQED, αQCD, MW, and mt, at the level of FCC-ee requirements was thoroughly discussed. The requirements on Standard Model theory calculations were spelt out, so as to meet the demanding accuracy of the FCC-ee experimental potential. The discussion of innovative methods and tools for multiloop calculations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were discussed, including effective theory approaches. The reports of 2018 and 2019 serve as white papers of the workshop results and subsequent developments.

  • SPS Beam Dump Facility: Comprehensive Design Study
    Vol. 2 (2020)

    Editors: M. Calviani, B. Goddard, R. Jacobsson and M. Lamont

    The proposed Beam Dump Facility (BDF) is foreseen to be located in the North Area of the Super Proton Synchrotron (SPS). It is designed to be able to serve both beam-dump-like and fixed-target experiments. The SPS and the new facility would offer unique possibilities to enter a new era of exploration at the intensity frontier. Possible options include searches for very weakly interacting particles predicted by Hidden Sector models, and flavour physics measurements. Following the first evaluation of the BDF in 2014–2016, CERN management launched a Comprehensive Design Study over three years for the BDF. The BDF study team has executed an in-depth feasibility study of proton delivery to target, the target complex, and the underground experimental area, including prototyping of key subsystems and evaluations of radiological aspects and safety. A first iteration of detailed integration and civil engineering studies has been performed to produce a realistic schedule and cost. This document gives a detailed overview of the proposed facility together with the results of the in-depth studies, and draws up a road map and project plan for a three years Technical Design Report phase and a five–six years construction phase.

  • SEE-LS: A 4th Generation Synchrotron Light Source forScience and Technology
    Vol. 1 (2020)

    Editor: Dieter Einfeld 

    In 2016 the South East Europe International Institute for Sustainable Technologies was proposed by Herwig Schopper and brought to the political level by Sanja Damjanović, Minister of Science of Montenegro. In this framework two design studies have been completed by two groups of European experts: a South East Europe ‘4th Generation Synchrotron Light Source for Science and Technology’ (SEE-LS) and a ‘Facility for Tumour Hadron Therapy and Biomedical Research’. This report concerns the SEE-LS study, which was completed in October 2018. The proposal is to build a 4th generation light source with a circumference of 350 m and 16 straight sections and with an emittance of 178 pmrad for an energy of 2.5 GeV. In a later stage, the machine could be upgraded to 3 GeV. The estimated budget is roughly  170 million Euro, and the first X-rays should be produced in six years. Readers who are not interested in the details can refer to the Executive Summary.

  • Physics of the HL-LHC, and perspectives at the HE-LHC
    Vol. 7 (2019)

    Editors: A. Dainese, M. Mangano, A. B. Meyer, A. Nisati, G. Salam and M. Vesterinen

    This report comprises the outcome of five working groups that have studied the physics potential of the high-luminosity phase of the LHC (HL-LHC) and the perspectives for a possible future high-energy LHC (HE-LHC). The working groups covered a broad range of topics: Standard Model measurements, studies of the properties of the Higgs boson, searches for phenomena beyond the Standard Model, flavor physics of heavy quarks and leptons and studies of QCD matter at high density and temperature. 

    The work is prepared as an input to the ongoing process of updating the European Strategy for Particle Physics, a process that will be concluded in May 2020.

  • History of the European Muon Collaboration (EMC)
    Vol. 5 (2019)

    The European Muon Collaboration (EMC), formed in the years 1972–1974, was one of the first large experimental particle physics collaborations with more than 100 physicists. Its aim was to study the quark structure of the nucleon through deep inelastic muon scattering. Two seminal discoveries were made; the EMC effect and the spin crisis. In this paper the history of the collaboration from beginning to end is described. The appendices describe some of the difficulties met during the development and performance of the experiments as well as a description of some of the social interactions in the collaboration.

  • Study on the career trajectories of people with a working experience at CERN
    Vol. 4 (2019)

    This document describes the results of a study, aiming to measure the impact of CERN and of its environment on the career of people who worked at the laboratory. The data was collected using two on-line question- naires, launched in 2016 and 2017, targeting experimentalists and theorists, respectively. The mandate, the methodology followed, the questionnaires and the analysis of the data collected are presented.

  • Standard Model Theory for the FCC-ee Tera-Z stage
    Vol. 3 (2019)

    Report on the Mini Workshop Precision EW and QCD Calculations for the FCC Studies: Methods and Tools, 12–13 January 2018, CERN, Geneva.
  • A Facility for Tumour Therapy and Biomedical Research in South-Eastern Europe
    Vol. 2 (2019)

    Editor: Ugo Amaldi

    In 2016 the South East European International Institute for Sustainable Technologies (SEEIIST) was proposed by Herwig Schopper and brought to the political level by Sanja Damjanovic, Minister of Science of Montenegro. In this framework two design studies have been completed by two groups of European experts: a "4th Generation Synchrotron Light Source for Science and Technology" (SRL) and a "Facility for Tumour Hadron Therapy and Biomedical Research" (HTR). A preliminary report was presented and discussed at the Workshop on "New International Research Facilities for South East Europe" held in January 2017 at ICTP (Trieste). In March 2018 the Steering Committee came unanimously to the conclusion that the first facility to be built should be the HTR. This report contains the HTR study, which was completed in July 2018; the Executive Summary has been written for the readers who are not interested in the details.

  • Detector Technologies for CLIC
    Vol. 1 (2019)

    Editors: D. Dannheim, K. Krüger, A. Levy, A. Nürnberg, E. Sicking

    The Compact Linear Collider (CLIC) is a high-energy high-luminosity linear electron–positron collider under development. It is foreseen to be built and operated in three stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. It offers a rich physics program including direct searches as well as the probing of new physics through a broad set of precision measurements of Standard Model processes, particularly in the Higgs-boson and top-quark sectors. The precision required for such measurements and the specific conditions imposed by the beam dimensions and time structure put strict requirements on the detector design and technology. This includes low-mass vertexing and tracking systems with small cells, highly granular imaging calorimeters, as well as a precise hit-time resolution and power-pulsed operation for all subsystems. A conceptual design for the CLIC detector system was published in 2012. Since then, ambitious R&D programmes for silicon vertex and tracking detectors, as well as for calorimeters have been pursued within the CLICdp, CALICE and FCAL collaborations, addressing the challenging detector requirements with innovative technologies. This report introduces the experimental environment and detector requirements at CLIC and reviews the current status and future plans for detector technology R&D.

  • HIE-ISOLDE : Technical Design Report for the Energy Upgrade
    Vol. 1 (2018)

    edited by Y. Kadi, M. A. Fraser, A. Papageorgiou-Koufidou
    CERN-2018-002-M, 978-92-9083-492-2 (paperback), 978-92-9083-493-9 (PDF)
    The Isotope mass Separator On-Line facility (ISOLDE) at CERN occupies a leading position in the field of radioactive ion beams research, as it can produce the largest range of isotopes worldwide —over 1000 isotopes of more than 70 elements. HIE-ISOLDE (High Energy and Intensity – ISOLDE) is an upgrade that aims to increase the facility’s energy and intensity reach, opening the way to new opportunities in multiple fields of physics: nuclear and atomic physics, astrophysics and fundamental interactions. This technical design report presents the HIE-ISOLDE energy upgrade as built. The report is divided in six parts. The first details the motivation behind the project, as well as previous experiences with post-accelerated beams at the facility. The second part presents the design of the new linear accelerator and its components, including cryomodules, superconducting cavities and solenoids, while the third focuses on beam dynamics. General services and systems are presented in the fourth part, while the fifth and sixth concern safety procedures and commissioning respectively.
  • The Compact Linear Collider (CLIC) - 2018 Summary Report
    Vol. 2 (2018)

    Corresponding editors: Philip N. Burrows (University of Oxford), Nuria Catalán Lasheras (CERN), Lucie Linssen (CERN), Marko Petrič (CERN), Aidan Robson (University of Glasgow), Daniel Schulte (CERN), Eva Sicking (CERN), Steinar Stapnes (CERN)

    Abstract: The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e+e- collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years.

  • The CLIC potential for new physics
    Vol. 3 (2018)

    Corresponding editors: J. de Blas, R. Franceschini, F. Riva, P. Roloff, U. Schnoor, M. Spannowsky, J. D. Wells, A. Wulzer and J. Zupan

    Abstract: The Compact Linear Collider (CLIC) is a mature option for the future of high energy physics. It combines the benefits of the clean environment of e+e− colliders with operation at high centre-of-mass energies, allowing to probe scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model.

  • The Compact Linear Collider (CLIC) – Project Implementation Plan
    Vol. 4 (2018)

    Edited by: M. Aicheler, P.N. Burrows, N. Catalan, R. Corsini, M. Draper, J. Osborne,D. Schulte, S. Stapnes and M.J. Stuart

    Abstract: The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e+e- collider under development by international collaborations hosted by CERN. This document provides an overview of the design, technology, and implementation aspects of the CLIC accelerator. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, for a site length ranging between 11 km and 50 km.  CLIC uses a Two-Beam acceleration scheme, in which normal-conducting high- gradient 12 GHz accelerating structures are powered via a high-current Drive Beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments, and system tests have resulted in significant progress in recent years.  Moreover, this has led to an increased energy efficiency and reduced power consumption of around 170 MW for the 380 GeV stage, together with a reduced cost estimate of approximately 6 billion CHF. The construction of the first CLIC energy stage could start as early as 2026 and first beams would be available by 2035, marking the beginning of a physics programme spanning 25–30 years and providing excellent sensitivity to Beyond Standard Model physics, through direct searches and via a broad set of precision measurements of Standard Model processes, particularly in the Higgs and top-quark sectors.

  • Feasibility Study for BioLEIR
    Vol. 1 (2017)

    Edited by S. Ghithan, G. Roy, S. Schuh

    CERN-2017-001-M, ISBN (Print) 978–92–9083–440–3, ISBN (PDF) 978–92–9083–441–0

  • Handbook of LHC Higgs cross sections: 4. Deciphering the nature of the Higgs sector
    Vol. 2 (2017)

    Edited by D. de Florian, C. Grojean, F. Maltoni, C. Mariotti, A. Nikitenko, M. Pieri, P. Savard, M. Schumacher, R. Tanaka

    CERN-2017-002-M, ISBN (Print) 978–92–9083–442–7, ISBN (PDF) 978–92–9083–443–4

  • Physics at the FCC-hh, a 100 TeV pp collider
    Vol. 3 (2017)

    Edited by M. L. Mangano

    CERN-2017-003-M, ISBN (Print) 978–92–9083–453-3, ISBN (PDF) 978–92–9083–454-0

  • High-Luminosity Large Hadron Collider (HL-LHC) Technical Design Report V. 0.1
    Vol. 4 (2017)

    edited by Apollinari G., Béjar Alonso I. (Executive Editor), Brüning O., Fessia P., Lamont M., Rossi L., Tavian L.
    CERN-2017-007-M, ISBN 978-92-9083-470-0 (paperback), ISBN 978-92-9083-471-7 (PDF)

  • Archive of CERN Yellow Reports: Monographs since 1955

    You can find all monographs published since 1955 at this link.