During the last 10 years, major discoveries have shaped our vision of the building  blocks of matter, their properties, their interactions and their role in the evolution of the Universe. With the discovery of the Higgs boson, the Standard Model of Particle Physics provides an internally consistent picture of the known elementary particles which is nevertheless known to be incomplete, since it leaves several major questions unanswered. The presence of Dark Matter in current cosmological models, and the fact that gravity is not included in the  Standard Model, are two examples which push searches for physics beyond the Standard Model.

New physics models which address these questions can, for example, lead to deviations Standard Model in consistency tests or in the properties of the Higgs boson at the sub per cent level, and/or predict new particles or forces which manifest at the higher  energies than currently accessible. Reaching high precision and extending the energy range are therefore crucial.

Searches for Dark Matter continue at colliders, direct detection experiment and via indirect observation via astrophysics. So far none of these have revealed any signature of new particles, though theoretical as well as experimental efforts are continuously pushing the limits. Other promising areas to look for deviations from the Standard Model include high precision measurements in flavour physics in the quark and charged lepton sectors, and the search of broken symmetries in the neutrino sector.

A key goal for Nuclear Physics is to develop a comprehensive understanding and a predictive theory of complex nuclei. Worldwide, this goal has driven the development of various cutting edge facilities for experiments with short-lived rare isotopes in order to provide data and discover new phenomena against which theoretical predictions have to be tested. Rare isotope beams (RIB) are obtained by complementary techniques, either through the isotope-separation- on-line (ISOL) process or through inflight production. Such beams will allow for nuclear physics research studies aiming at answering several fundamental questions related to the phases of strongly interacting matter and their role in astrophysics, the nature of the strong force that binds protons and neutrons into stable and rare isotopes, the nature of neutron stars and dense matter, the nuclear reactions that drive stars and stellar explosions. Nuclear structure and dynamics have not only reached the discovery frontier, but are also entering into a high precision frontier with higher beam intensities and purity, along with better efficiency and sensitivity of instruments, in order to focus on essential observables to validate and guide our theoretical developments.

Current Status

The current Particle Physics landscape is guided by the 2013 European Strategy for Particle Physics (ESPP)European Strategy for Particle Physics (ESPP) https://cds.cern.ch/record/1567258/files/esc-e-106.pdf, which has been closely followed providing a coherent and broad scientific programme. The Large Hadron Collider (LHC) at CERNHL-LHC https://home.cern/topics/high-luminosity-lhc is the major infrastructure for particle physics, with more than 7.000 physicists working on its different experiments. By the end of 2018,  the LHC is in its second running period and will have accumulated an integrated luminosity of 150 fb^-1, corresponding to acquiring the data of roughly 10¹⁵ collisions and a stored data volume well in excess of 250 PB. In 2019-2020 a long shutdown is foreseen with major detector upgrades of the LHC experiments. It is foreseen to accumulate another 150 fb-1 in this configuration until the high-luminosity phase of the LHC will start around 2025. The ESFRI Landmark HL-LHC (High-Luminosity Large Hadron Collider) requires an upgrade of the accelerator complex, which has already started, and also refurbishment of the ATLAS and CMS detectors in order to maximise their scientific output in a much harsher environment.

In the field of flavour physics, the measurements provided by the LHCb experiment will be complemented and cross-checked by the results from the BELLE-2 experiments at the SuperKEKBSuperKEKB http://www-superkekb.kek.jp/index.html collider at KEK in Japan. Data taking of this experiment will start in 2019 and use rather low energy electron-positron beams yet at the highest intensities with the aim to accumulate an integrated luminosity of 50 ab^-1.

The CERN neutrino platform is a framework that allows European physicists to work on neutrino detector development. In this context, collaboration is ongoing with the next generation long baseline accelerator- based neutrino experiments: DUNE in the US (Fermi National Accelerator Laboratory FNALFermi National Accelerator Laboratory (FNAL) http://www.fnal.gov/ and Sanford Underground Research FacilitySanford Underground Research Facility https://sanfordlab.org) and Hyper-Kamiokande Hyper-Kamiokande http://www.hyperk.org in Japan.

These experiments with increased beam intensities, and improved detectors, will allow unprecedented precision in measurements of neutrino oscillations and CP violation. Detector R&D as well as prototype construction for these experiments is ongoing. Accelerator based neutrino experiments are complemented by the upcoming reactor-based experiment, JUNO located in China, and measurements with atmospheric neutrinos by the ORCA-site of the ESFRI Project KM3NeT 2.0 collaboration. Other neutrino properties are measured in Europe by smaller infrastructures, such as KATRIN at KIT for aiming at a direct neutrino mass measurement, and GERDA, CUORE at LNGS or SuperNemo (LSM) for determining the Dirac or Majorana nature of neutrino. European particle physicists are also pursuing precision measurements in the charged-lepton sector, at PSI and at infrastructures in other regions (US, Japan).

Complementing the searches for new physics at the LHC, experiments directly searching for Dark Matter based on various techniques such as liquid noble gas or cryogenic detectors are hosted in underground laboratories. The most stringent  limits are currently provided by the XENON collaboration (LNGS), with developments ongoing on large liquid Argon based detectors (DARKSIDE) and low mass searches with cryogenic detectors.

The first generation of radioactive beam (RIB) facilities based on the complementary methods of, in flight separation (GANIL and GSI) and the ISOL approach (ISOLDE and SPIRAL1) have enabled tremendous progress in the study of exotic nuclei to be made. Both in-flight separation and the ISOL approach, combined with different post-processing of the radioactive nuclei, will form the pillars of the RIB facility network in Europe.

Major advances in the field are expected to come through the studies of extended reach in proton-to-neutron ratio of new or upgraded facilities, including the Radioactive Isotope Beam Factory (RIBF) at Rikagaku Kenkyusho (RIKEN), the ESFRI Landmark FAIR (Facility for Antiproton and Ion Research) at Darmstadt, the HIE-ISOLDE facility at CERN, the ESFRI Landmark SPIRAL2 (Système de Production d’Ions Radioactifs en Ligne de 2e génération) at Grand Accelerateur National D’ions Lourds (GANIL), the facility for the Study and Production of Exotic Species (SPES) at INFN-Legnaro, the Isotope Separation and Acceleration II (ISACII) at TRIUMF, and the Facility for Rare Isotope Beams (FRIB, USA) with capabilities for fast, stopped, and unique reaccelerated beams. All these facilities provide or will provide new and important insights into the structure of nuclei and are expected to discover new phenomena that will lead to major progress towards a unified description of nuclei. Other accelerator-based probes are also important for nuclear physics researchin Europe. The ELI-NP (Extreme Light Infrastructure - Nuclear Physics) facility is one of the three pillars of the pan-European ESFRI Landmark ELI aiming at the use of extreme electromagnetic fields for nuclear physics research.

Investigation of nuclei produced at the upcoming nuclear physics research facilities requires development of state-of-theart detectors and detection techniques. The Advanced Gamma Tracking Array (AGATA)Advanced Gamma Tracking Array (AGATA) https://www.agata.org/ represents a revolution in the way gamma-ray spectroscopy is performed and it will have a wide range of uses in nuclear physics from studying how elements are synthesised in stars to the understanding of the underlying shell structure of the newly discovered super-heavy elements. The basic technology of the array will also bring developments in medical imaging and diagnostic machines that produce three-dimensional images of people’s bodies, providing information about the functioning of internal organs and detecting disease and tumours.

The production of exotic nuclei is closely linked to the availability of separators and spectrometers in order to select and identify the nuclei or reactions of interest. Addressing these objectives is a driving force for existing or future facilities, such as the Japan Proton Accelerator Research Complex (J-PARC), the international ESFRI Landmark FAIR at Darmstadt, the 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF) Upgrade at the Jefferson Lab, the Mainz Microtron (MAMI), A Large Ion Collider Experiment (ALICE) at CERN, and RHIC II at Brookhaven National Laboratory (BNL), the Nuclotron-based Ion Collider fAcility (NICA) or The Super Heavy Element Factory (SHE Factory) at the Joint Institute for Nuclear Research (JINR) in Dubna (Russia).

A summary of the main Research Infrastructures in Particle and Nuclear Physics field is shown in Figure 3 and ESFRI contribution is depicted in Figure 4.

Figure 3. Major Research Infrastructures in Particle and Nuclear Physics

Figure 4. Space and time domain of investigation of ESFRI Projects and Landmarks in Particle and Nuclear Physics

Gaps, challenges and future needs

For the near term future, the HL-LHC will be the main particle physics accelerator infrastructure, allowing detailed study of the Higgs sector and searches for new physics with 3000 fb-1 of data expected for ATLAS and CMS by 2035. On a similar timescale an International Linear Collider (ILC)International Linear Collider http://www.linearcollider.org/providing electron-positron collisions at a few hundred GeV energy, is a possible project to be hosted in Japan as a worldwide international collaboration. This would allow important studies of the Higgs sector and other precision measurements complementary to the HL-LHC. The ILC has long been on the strategic list of projects foreseen in particle physics, and a signal from the Japanese community indicating whether or not Japan would host such a project is expected by the end of 2018.

Further future projects would address the two main requirements for particle physics: an increase in precision and in energy. Several initiatives in accelerator R&D are addressing these challenges. In order to reach higher energies for an electron-positron linear collider, R&D for the CLIC concept using beam driven acceleration has been pursued at CERN initially aiming at energies in the multi-TeV range. However, the highest reach in energy is obtained from proton colliders, where the big challenge is the development of high field magnets, currently part of an ambitious R&D programme. Conceptual studies for a 100 km collider with about 100 TeV collision energy – the Future Circular Collider Study (FCC)Future Circular Collider Study https://fcc.web.cern.ch/Pages/default.aspx are underway at CERN. Such a collider would open a new window on searches for new physics and allow a conclusive study of the Higgs self-coupling. A possible stepping stone could be to install the required high field magnets in the LHC tunnel to double the LHC collision energy (HE-LHC), or to have an electron-positron collider in the FCC tunnel (FCC-ee), both of which are included in the FCC studies. There may also be interesting options to combine these technologies to collide electrons with protons, which may provide significant improvement in Higgs coupling measurements. Beyond these studies, innovative R&D programmes are ongoing on the concept of laser-plasma acceleration. Several techniques are studied in major European laboratories (Germany, Italy, UK, France and Portugal) and through the EUPRAXIAEUPRAXIA http://www.eupraxia-project.eu/ design study as well as through the AWAKEAWAKE https://cds.cern.ch/record/2221183/files/SPSC-SR-194.pdf project at CERN.

Given the lack of theoretical guidance on where new physics could be realized, it is important to, as much as possible, cover all options. A new Physics Beyond CollidersPhysics Beyond Colliders http://pbc.web.cern.ch/ initiative is looking at ways of profiting from the CERN infrastructure and expertise to leave no stone unturned in the search for new physics. For example, studies include searches for axion-like particles in beam dump based experiments benefitting from the upgrade of the LHC injectors. By the end of 2018 documents on all the above projects will be available for the next ESPP discussion, from which a set of recommendations will be released in 2020 to define the strategy for particle physics research for the proceeding 5-10 years.

For Nuclear Physics on a long term perspective a novel ISOL facility in Europe (EURISOL) is needed, which will provide wide range of beams with much higher intensities compared to what is available at present. Meanwhile, by integrating the ongoing efforts and developments at the major ISOL facilities of HIE-ISOLDE, SPES and SPIRAL2, the planned ISOL@MYRRHA facility, and the existing JYFL and ALTO and COPIN facilities and the planned ELI-IGISOL facility an advantage should be taken use the synergies and complementarities between them and build a programme of research to bridge the gap between present facilities and ultimate EURISOL facility.

Based on the collaboration between nuclear physicists and plasma physicists, the ELI project will develop laser–plasma electron accelerators, based on the wakefield principle, and ion beams accelerators. Such devices have the potential to accelerate a range of particle and ion species in table-top distances. These innovative acceleration methods will open new perspectives for a range of applications such as: more efficient production of radioisotopes required for nuclear medicine and beams for testing the latest designs of sensors for use in medical imaging, new methods for identification and remote characterization of nuclear materials with applications in homeland security and nuclear material management, testing of materials for space science.

Research and development programmes, are being pursued to investigate the concept of precision storage rings to search for charged particle electric dipole moments (EDM), based on the ongoing studies at COSY; the design of a polariser ring to produce high intensity polarized antiproton beams as one upgrade option for HESR at FAIR; the implementation of sympathetic laser cooling techniques to cool systems like the proton, antiproton and highly charged ions to temperatures as low as a few mK; the design of advanced high intensity lasers for precision spectroscopy of exotic atoms, such as antihydrogen, muonic hydrogen, pionic helium, and muonium.