CERN, in search of the secrets of the universe
The physicists of the European Organization for Nuclear Research, near Geneva, probe the fundamental building blocks of matter. This is the third instalment of our series of articles on Swiss universities and research institutes.
If you can read this article and check your Facebook notifications it is to some extent thanks to the European Organization for Nuclear Research (CERN). Tim Berners-Lee, a British physicist, invented the World Wide Web, i.e. the internet, in 1989 while working at CERN. The original aim was to facilitate the exchange of information between researchers working together on the primary mission of this prestigious laboratory of fundamental physics: to discover the laws of the universe.
CERN is located at Meyrin, in the canton of Geneva on the border of France and Switzerland. It employs almost 3,200 people from 21 member states, all European with the exception of Israel. Its activities however reach far beyond the European context. In total, some 12,000 scientists representing 600 institutes and universities, 70 countries and 120 nationalities contribute the results of their research. That is half of the world's particle physicists!
Switzerland was chosen to host CERN to a large extent because of its neutrality and its safeguards against the misappropriation of scientific research results for military purposes. This was especially important when the organisation was established in 1954 because the world was just entering the Cold War. Switzerland offers other advantages including its location in the heart of Europe, its tradition as host country to international organisations and its stability.
These are indispensable factors for carrying out scientific research and developing infrastructures of long duration because unmasking the laws of nature requires at the least a minimum of patience. "It involves understanding what matter is made of, that is to identify its fundamental or elementary constituent particles and to study how they interact with each other," explains Peter Jenni, 68, renowned CERN particle physicist, who until 2009 headed the ATLAS experiment, the largest detector of the Large Hadron Collider (LHC), which is the main working tool of the organisation's researchers.
The world's most powerful accelerator
A collider, or accelerator, is a linear or circular tube in which scientists collide particles at very high speeds. The result of the collisions is then analysed by the detectors. The LHC, which entered into service on 10 September 2008, is the most powerful collider ever built. Its underground circular tunnel is 27 km long and the particles, which are guided by superconducting magnets, are propelled at speeds approaching the speed of light. Its successor, which is currently under study, might even run under Lake Geneva.
Experiments conducted in 2012 using the LHC confirmed the existence of the Higgs boson, which had already been suggested in 1964. The 'God particle', as it is sometimes called, is associated with the Brout-Englert-Higgs field which, put simply, fills the empty space around us and in space, and gives mass to elementary particles, as two CERN physicists explain in this short animation:
The Higgs boson is the missing piece of the standard model of particle physics, which was developed in the 1970s and explains how particles of matter work and how three of the four fundamental forces – including electromagnetism, but not gravity – govern the universe. It was therefore a major discovery. But the work didn't stop there.
"One of the objectives of the current season (editor's note: the LHC was restarted at the end of March after a winter break) is to get a better insight into the Higgs boson, explains Peter Jenni. Many questions remain open and more data are required. It could be for instance that there is not just one boson but several." CERN hopes to obtain a volume of data seven to ten times greater than what was available in 2015, the researcher stressed, recalling that the Higgs boson is by no means the only focus of physicists' work: "Many areas of fundamental physics are being studied in parallel."
Recreating the dark matter particle
One of the LHC's functions is to enable exploration of the theories that don't fit the standard model, such as 'supersymmetry'. "Supersymmetry is very popular because it postulates the existence of a particle that would have been created just after the Big Bang and which could be responsible for dark matter." Dark matter is this invisible matter that holds the galaxies together through a gravitational force effect. "With the energy of the LHC we might be able to reproduce the conditions in which this particle was created. This is one of our main priorities."
One mysterious particle has recently created a buzz. At the end of December 2015, CERN announced that it had identified an irregularity in the data provided by the ATLAS and CMS detectors of the LHC, which would point to the – unexpected – existence of a particle six times bigger than the Higgs boson. The media and scientists around the world got very excited about this. But Peter Jenni pours cold water on the idea: "What we found is not statistically significant and will most probably disappear once we have collected more data."
The widespread interest in this anomaly nevertheless reveals much about the current state of physics, explains Peter Jenni: "What got people so excited was the fact that it was something new that was not predicted by the classical theories. It is important to understand that the standard model is not complete but an approximation. We need to find indicators to enable us to know in which direction physics could develop beyond this paradigm."
CERN not only explores our universe through physics, but also through culture. In 2011, CERN launched the Arts@CERN initiative that aims to promote dialogue between the arts, science and technology. Residency programmes are offered to develop projects at the interface of these disciplines. The laboratory has already opened its doors to dozens of artists. Who says that science and spirituality are incompatible?