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Particle and nuclear

Particle and nuclear

Mark Thomson and Jung Cao: a changing of the guard in particle physics

27 Nov 2024 Matin Durrani
Fractal art created from particle paths in the Large Hadron Collider
(Courtesy: Shutterstock/sakkmesterke)

All eyes were on the election of Donald Trump as US president earlier this month, whose win overshadowed two big appointments in physics. First, the particle physicist Jun Cao took over as director of China’s Institute of High Energy Physics (IHEP) in October, succeeding Yifang Wang, who had held the job since 2011.

Over the last decade, IHEP has emerged as an important force in particle physics, with plans to build a huge 100 km-circumference machine called the Circular Electron Positron Collider (CEPC). Acting as a “Higgs factory”, such a machine would be hundreds of times bigger and pricier than any project IHEP has ever attempted.

But China is serious about its intentions, aiming to present a full CEPC proposal to the Chinese government next year, with construction staring two years later and the facility opening in 2035. If the CEPC opens as planned in 2035, China could leapfrog the rest of the particle-physics community.

China’s intentions will be one pressing issue facing the British particle physicist Mark Thomson, 58, who was named as the 17th director-general at CERN earlier this month. He will take over in January 2026 from current CERN boss Fabiola Gianotti, who will finish her second term next year. Thomson will have a decisive hand in the question of what – and where – the next particle-physics facility should be.

CERN is currently backing the 91 km-circumference Future Circular Collider (FCC), several times bigger than the Large Hadron Collider (LHC). An electron–positron collider designed to study the Higgs boson in unprecedented detail, it could later be upgraded to a hadron collider, dubbed FCC-hh. But with Germany already objecting to the FCC’s steep £12bn price tag, Thomson will have a tough job eking extra cash for it from CERN member states. He’ll also be busy ensuring the upgraded LHC, known as the High-Luminosity LHC, is ready as planned by 2030.

I wouldn’t dare tell Thomson how to do his job, but Physics World did once ask previous CERN directors-general what skills are needed as lab boss. Crucial, they said, were people management, delegation, communication and the ability to speak multiple languages. Physical stamina was deemed a vital attribute too, with extensive international travel and late-night working required.

One former CERN director-general even cited the need to “eat two lunches the same day to satisfy important visitors”. Squeezing double dinners in will probably be the least of Thomson’s worries.

Fortuantely, I bumped into Thomson at an Institute of Physics meeting in London earlier this week, where he agreed to do an interview with Physics World. So you can be sure we’ll get Thomson put his aims and priorities as next CERN boss on record. Stay tuned…

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