Mark Thompson on CERN’s High Luminosity LHC Upgrades, Antimatter, and the Future of Particle Physics

Overview

In this New Scientist interview, CERN Director General Mark Thompson discusses the High Luminosity Large Hadron Collider (HL-LHC) upgrade, the rationale behind upgrading magnets on the surface before underground installation, and the broader goals of probing dark matter and the Higgs boson. He also touches on the antimatter factory, CPT tests, and future collider plans such as the Future Circular Collider (FCC), alongside CERN's non collider science program and European collaboration.

The conversation emphasizes the scale of CERN’s projects, the strategic importance of big bets in physics, and the potential long term societal and technological benefits of fundamental research.

Introduction and context

The interview is set at CERN and features Mark Thompson, the Director General, discussing the organization’s mission to understand the universe at a fundamental level through high energy physics. The discussion begins with the LHC and why CERN pursues ever larger and more capable machines.

The HL-LHC upgrade and testing

Thompson explains a four year shutdown beginning in 2026 during which 1.2 kilometers of the 27 kilometer LHC ring will be replaced with advanced high field superconducting magnets. The magnets increase collision density, enabling many more proton-proton interactions per bunch crossing and thus far more data. Tests are conducted on the surface to simplify logistics given the tunnel’s tight spaces, before installation underground.

Scientific goals and discoveries

The conversation covers the big questions driving the field: the nature of dark matter, whether the Higgs boson is a fundamental particle, and how the Higgs field gives mass to other particles. Thompson argues we are in a period where multiple major questions remain, even as the field has seen breakthrough moments like the discovery of the Higgs boson in 2012 and neutrino mass measurements.

The future of colliders and the FCC

Looking ahead, the FCC is positioned as the best scientific bet among proposed next generation machines. The FCC would start as an electron–positron collider with the potential to later evolve into a hadron collider, offering unprecedented sensitivity at the electroweak scale. Thompson frames the FCC as a long term path that could guide discoveries for the next several decades, depending on what future data reveal.

Antimatter program and CPT tests

The antimatter program at CERN, including the Antiproton Decelerator (AD) and base step concepts, is described as a precision test of fundamental symmetries. By trapping antimatter in sophisticated magnetic traps, researchers compare matter and antimatter properties with extreme precision to test CPT invariance and look for any deviations from expected behavior.

Non collider science and the Science Gateway

Thompson emphasizes CERN’s broader program, noting active non collider research and a Science Gateway that welcomes the public to explore the science behind CERN’s work. He highlights that science communication and public engagement are integral to CERN’s mission.

Global collaboration and economy

The director discusses the European model of collaboration, funding challenges in a difficult economy, and the importance of big bets in science. He argues that investment in large projects yields long term technological and economic benefits, citing examples such as the World Wide Web and proton therapy technology that came from accelerator research.

Conclusion

Thompson remains optimistic about breakthroughs that may emerge in the next decade, asserting that the right questions are being asked and that the exploration of the universe remains a powerful driver of scientific and technological progress.