New detector in CERN: the key role of Belgian scientists

An interuniversity team of 40 Belgian scientists has begun production of these parts, which will be incorporated into the new version of CMS, one of CERN's two major particle detectors. Its mission is a major one: to build 1,600 high-precision modules in 2 years! 

In a clean room at the Interuniversity Institute for High Energies (IIHE-ULB/VUB) in Brussels, the first modules have already seen the light of day. They are the fruit of collaboration between researchers, physicists and engineers from ULB, VUB, UCLouvain, UGent and UAntwerpen. These Belgian universities have been asked to design and build one of the components of the new trajectograph that will be integrated into the new-generation CMS and will be capable of detecting the trajectories of thousands of particles produced by collision, 40 million times per second.

The CMS (Compact Muon Solenoid) is one of the two large particle detectors built at CERN's Large Hadron Collider (LHC) on the French-Swiss border near Geneva. However, the current LHC has reached its maximum capacity and will be shut down for four years in the summer of 2026. During this break, CERN's accelerator complex will be upgraded to produce up to 10 times more collisions than currently, in a new run of collisions scheduled to last from 2030 to 2041. This new detector, with its exceptional characteristics, should lead to decisive advances in our understanding of matter.

This is the backdrop to the Belgian scientists' mission, in addition to significant support from the Fonds de la Recherche Scientifique (FNRS) and the Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO), which have together allocated more than €12 million to the upgrade of the CMS experiment. 

Belgium has always made a major financial and scientific contribution to CERN, and to CMS in particular. Around a hundred Belgian scientists are currently working on this experiment, which brings together 4,000 researchers from all over the world. CMS is one of the two experiments that led to the discovery of the Brout-Englert-Higgs boson in 2012, which confirmed a theory developed almost 50 years earlier and for which our compatriot François Englert in particular was awarded the Nobel Prize in 2013. Since the discovery of this boson, the LHC has continued to produce collisions that have improved our understanding not only of this remarkable particle, but also of particle physics in general and of new phenomena beyond the Standard Model. This was particularly the case last March with the uncovering of an excess in the production of pairs of top quarks, forming a kind of astonishing molecule in which each quark risks disintegrating even before bonding with the other quark.