European Organization for Nuclear Research (CERN): Mid-term plan for 2024–2028, including upgrades, future collider studies, accelerator technology and R&D, etc.

Key Chapter Title List

1. Overall Strategy and Director-General's Observations
2. Scientific Programme
3. High-Luminosity LHC and Detector Upgrades
4. Accelerator Development
5. SHIP Experiment
6. Neutrino Platform
7. FCC Study
8. Other Activities
9. Major Changes Since the Last Medium-Term Plan
10. 2025-2029 Resource Plan
11. 2025 Draft Annual Budget
12. Key Performance Indicators

Document Introduction

This report is a medium-term strategic and financial planning document prepared by the European Organization for Nuclear Research (CERN) for the fiscal years 2025 to 2029, aiming to provide member states and the Council with a clear scientific roadmap and budget framework. The report's preface points out that CERN has successfully navigated the financial crisis of 2022-2023 triggered by high inflation and energy market prices. Through multiple measures including additional funding from member states, internal cost-saving, and declining energy costs, the cumulative budget deficit has been restored to a manageable level. This lays a relatively stable financial foundation for the ambitious scientific program of the next five years.

The core scientific program chapter systematically outlines the key milestones and long-term layout for the next five years. 2025 will be the final year of the current LHC run (Run 3), followed by the three-year third Long Shutdown (LS3, 2026-2028) to install High-Luminosity LHC upgrade components and the Phase-2 upgrades of the ATLAS and CMS detectors. The report details the progress of the HL-LHC project, including the development of the critical inner triplet superconducting magnets, the decision to internalize the manufacturing process for beryllium beam pipes, and the technical challenges and supply chain issues faced by the ATLAS and CMS Phase-2 detector upgrades. Furthermore, the report emphasizes the importance of a diversified physics program beyond colliders, involving the SHIP experiment, the Neutrino Platform's support for the DUNE experiment, and various fixed-target experiments supported by the Physics Beyond Colliders study group.

The report dedicates significant space to forward-looking technology research and development. Accelerator R&D focuses on repairing critical equipment (such as TDIS), the beam screen treatment project to address electron cloud effects, and strengthening superconducting radio-frequency cavity technology R&D to lay the technical groundwork for future options like circular colliders and muon colliders. The Efficient Particle Accelerators project aims to automate and optimize accelerator operations using artificial intelligence and machine learning. The focus of future collider research is on completing the feasibility study for the Future Circular Collider (FCC) and entering the pre-Technical Design Report phase after March 2025, to inform a Council decision by the end of 2027 or early 2028.

The financial planning section details the 2025-2029 revenue and expenditure plans, comparing them with the previous year's plan. Major new expenditures cover increased HL-LHC project costs, the ECN3 experimental hall upgrade, the SHIP experiment, the Neutrino Platform's commitment to DUNE, consolidation and maintenance of various accelerators and infrastructure, and additional resources for the FCC feasibility study and pre-TDR phase. New revenue primarily comes from Brazil's accession as an Associate Member State. Simultaneously, due to a significant drop in electricity market prices, the report achieves considerable budget savings. Through these revenue and expenditure adjustments, the report forecasts that the cumulative budget deficit will peak in 2027 and then gradually decline, approaching zero in the early 2030s. Through rigorous data and charts, the entire report demonstrates CERN's comprehensive planning and risk assessment in balancing frontier scientific exploration, large-scale project implementation, and fiscal sustainability.