On 29 September this year, CERN, a European laboratory for particle physics, the place where the web was born in 1989 and the Higgs boson was discovered in 2012, celebrated its 70th anniversary. The impetus came from Louis de Broglie, a French theoretical physicist and 1929 Nobel Prize winner in Physics, who proposed the establishment of a European physics laboratory in 1949 to prevent the outflow of talented physicists to the US.
The twelve founding countries (Belgium, Denmark, France, the Federal Republic of Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, the United Kingdom and Yugoslavia) were later joined by twelve other countries (Austria, Spain, Portugal, Finland, Poland, the Czech Republic, Slovakia, Hungary, Bulgaria, Romania, Israel and Serbia). The original and still official name, the European Organization for Nuclear Research, however, no longer corresponds to the focus of CERN's activities or its geographical definition. In addition to the full members, CERN also has associate members and Japan and the United States have observer status. The Czech Republic became a full member of CERN on 1 July 1992 as part of the Czech and Slovak Federal Republic and again on 1 January 1993 as an independent state, as did Slovakia.
CERN and the Standard Model
The discovery of the Higgs boson at the LHC in 2012 completed the development of the Standard Model, a theoretical framework containing the basic building blocks of matter and the forces between them. This model has been developed for 80 years since the discovery of the neutron and positron in 1932, and in addition to the aforementioned Higgs boson, CERN has contributed two other major discoveries.
In 1973, it was CERN that for the first time observed processes in which muon neutrinos scattered elastically in collisions with electrons and nuclei as predicted by the theory of electroweak interactions, the formulation of which won Sheldon Glashow, Steven Weinberg and Abdus Salam the 1979 Nobel Prize in Physics. And ten years later, antiproton-proton collisions revealed an electrically neutral particle, designated Z, which is responsible for this process, along with two electrically charged particles, W+ and W-, which were also predicted by the theory and which represent the so-called weak force carriers.
For this fundamental discovery, Carlo Rubbia and Simon van der Meer were awarded the Nobel Prize in Physics in 1984. The discovery showed that the basic idea of the Standard Model was correct, but the question of the existence of the Higgs boson, important in the Standard Model for its mathematical consistency, remained unanswered. A key role in answering this question was played by the LEP (Large Electron-Positron Collider) at CERN, where electron-positron collisions occurred at record energies from 1989 to 2000, and in whose tunnel today is the LHC (Large Hadron Collider), where counter-parallel beams of protons or heavy ions collide at the highest energies achieved.
The experiments at LEP did not discover the Higgs boson, although they were very close, but their precise measurements have significantly narrowed the range of masses that the Higgs boson of the Standard Model was supposed to have. And the ATLAS and CMS experiments at the LHC have found it just at the edge of this region. This was a triumph for the Standard Model and for CERN.
The Institute of Physics at CERN
Employees of the Institute of Physics have been actively participating in experiments at CERN since the 1960s, although this cooperation was politically restricted. Initially, it involved the participation of individual physicists directly in CERN experiments, and from the end of the 1970s, the participation of groups from the Institute of Physics of the then Czechoslovak Academy of Sciences and the Faculty of Mathematics and Physics of Charles University in two key experiments at CERN as part of groups at the United Institute of Nuclear Research in Dublin.
The NA4 experiment, initiated by the later director of CERN and Nobel laureate in physics Carlo Rubia, who in the 1980s investigated the structure of nucleons using deep inelastic scattering of muons on nucleons, and the DELPHI experiment at the aforementioned LEP accelerator.
After 1989, the Institute of Physics and Charles University became direct participants in this experiment. DELPHI was one of four experiments at the LEP accelerator, and it was precisely for effective communication within the large teams of these experiments that Tim Berners-Lee developed the World Wide Web in 1989. By waiving all copyrights and making it freely available in 1992, CERN has unleashed an avalanche of this communication tool into all walks of life.
A quick path to CERN
The fact that groups from the Institute of Physics of the Czech Academy of Sciences and the Faculty of Mathematics and Physics of Charles University participated very actively in the DELPHI experiment and, to a lesser extent, in other experiments, played a key role in our country's rapid membership in CERN. This was the main condition for acceptance, documenting readiness of the country to join CERN.
The second decisive circumstance was the fact that in the first transitional post-November management of the then Czechoslovak Academy of Sciences, the so-called Committee for the Management of the ČSAV Institutes, the Chairman of the Council for Foreign Relations was Professor Jiří Niederle, an employee of the Institute of Physics. He persuaded Armin Delong, then Vice-Chairman of the Czechoslovak Academy of Sciences and Deputy Chairman of the Federal Government of the Czech and Slovak Federal Republic for Scientific and Technological Development, to visit CERN in March 1990 at the head of a government delegation and to sign a cooperation agreement.
In January 1991, a CERN delegation visited the Czech institutions that were cooperating with CERN and in its report stated our full readiness to join CERN. On 20 December 1991, the CERN Council unanimously approved the accession of the then Czechoslovak Republic to CERN with effect from 1 January 1992.
Prior to that, on 14 August 1991, the Czech Government of Petr Pithart had approved this step, and at the end of November 1991, President Václav Havel, accompanied by Jiří Niederle, visited CERN and met the then Director General of CERN, Carlo Rubbia.
After the division of the Czechoslovak Republic into two independent republics, both joined CERN again on 1 January 1993 and Jiří Niederle was appointed Chairman of the Committee for Cooperation of the Czech Republic with CERN and one of the two representatives of the Czech Republic on the CERN Council, the highest body of this intergovernmental organisation. Jiří Niederle held both of these positions until the spring of 2010, when advancing illness prevented him from continuing in the office. The recognition that Jiří Niederle gained at CERN is evidenced by the fact that he was Vice President of the CERN Council from 1995 to 1998.
Present
Today, CERN is the world's leading laboratory for elementary particle physics, with the world's largest accelerator, the Large Hadron Collider (LHC), and a highly developed network of smaller accelerators. The ATLAS experiment, in which groups of physicists and technicians from FZU and other Czech institutions have been and are involved at various stages, is currently primarily focused on the search for signals of "new physics", i.e. phenomena and structures that are not part of the Standard Model.
Although it is mathematically fully consistent and quantitatively describes all the processes observed so far in the microworld, it has some flaws. Above all, it does not contain gravity and it does not include a particle that is a candidate for the dark matter in the universe that seems to be necessary to understand the present state of the universe. That is why physicists have been trying for half a century to formulate extensions to the Standard Model to include structures and forces that would allow for these deficiencies to be eliminated.
There are several directions where and how to look for signals of new physics at the LHC, but they all require as many collisions as possible because we are looking for very rare phenomena. There are already a billion collisions of two protons flying towards each other every second at the LHC, and still no such signals have been found. Yet the LHC accelerator and the detectors of the ATLAS experiment and the other three experiments are working perfectly.
Future
To secure CERN's medium-term prospects, the HL-LHC Upgrade, a project to fundamentally upgrade the LHC accelerator and all its detectors, was approved by the CERN Council in 2016 with the aim of achieving a roughly fivefold increase in the frequency of two-proton collisions compared to the current state. Under the latest scenario, the current run of the LHC will end around mid-2026, after which a roughly three-year period of rebuilding the accelerator and detectors for this increased collision rate will begin.
In 2030, the next phase of experiments is expected to start, lasting at least 10 years. At the end of HL-LHC operation, the total number of collisions recorded should reach 10 times the previous number of collisions. This gives legitimate hope that during this new phase of LHC operation and experimentation, a discovery will be made that will fundamentally advance our understanding of structures and forces in the microworld. The preparatory phase of this project is already underway, with FZU playing an active part.
As massive accelerators take decades to plan and build, there is already a complementary project to the LHC at CERN, the Future Circular Collider (FCC), which is aimed at studying in great detail the properties of the Higgs boson in electron-positron collisions, which may also hold information about new physics. A large majority of elementary particle physicists agree that such project is needed, but it requires the construction of an entirely new circular collider. It is expensive, and would therefore require significant participation of countries from outside CERN. Moreover, the FCC is scheduled to start operating around 2050. It is a very good thing that CERN has a clear and agreed medium-term plan and an ambitious long-term plan for the construction of the FCC, the implementation of which will depend on whether, or what, new phenomena are discovered by the HL-LHC experiments, and also on the approval and progress of a similar project in China.
CERN and technology
But CERN is not just a laboratory for elementary particle physics, it is also a centre where new technologies are created. Not only the WWW, but also many other cutting-edge technologies originally developed for experiments at CERN have found applications in a wide range of other activities.