How A Rejected Proposal To Mussolini Sparked The Birth Of CERN

When Enrico Fermi met Benito Mussolini at Palazzo Venezia in January 1930 to request a national institute of physics, he walked away empty-handed, setting in motion a chain of events that would eventually reshape global science. Decades later, from the ruins of post-war Europe, visionary researchers carved out the foundations of modern particle physics by creating both Italy’s National Institute of Nuclear Physics and the European Organization for Nuclear Research, better known as CERN.

How a Rejected Proposal Triggered a Scientific Exodus

Fermi’s initial failure to secure state backing in 1930 was only the first hurdle. Years later, after discovering the extraordinary effectiveness of slow neutrons in producing artificial radioisotopes, Fermi wrote to the Italian National Research Council (CNR) proposing a National Institute of Radioactivity. Although a modest contribution was finally approved in 1938, the persistent institutional resistance contributed heavily to Fermi’s decision to emigrate to the United States after collecting his Nobel Prize in Stockholm. Italy was left with a depleted talent pool, but the determination of a handful of physicists who stayed behind would soon change the nation’s scientific destiny.

By 1946, a year after the end of World War II, a convergence of brilliant minds and unexpected experimental results breathed new life into Italian research. Gilberto Bernardini was called to Rome to teach general physics, while Marcello Conversi, Ettore Pancini, and Oreste Piccioni published a landmark study on the decay of cosmic ray particles known then as mesotrons. Their ingenious apparatus allowed researchers to measure negative and positive particles separately as they stopped in iron or carbon targets. The details of these historic efforts are explored in the Conference of the National Academy of Lincei and National Research Council proceedings published in 2027 by Ugo Amaldi.

The Unexpected Particle That Sparked a Revolution

The results obtained by Conversi, Pancini, and Piccioni stunned the physics community. According to prevailing theories, these particles should have interacted strongly with atomic nuclei, but the data proved otherwise. Fermi discussed the anomaly with Edward Teller, and a short paper co-written with Victor Weisskopf soon concluded that the interaction was many orders of magnitude smaller than predicted. From that moment, it became clear that these particles were not the nuclear glue predicted by theorist Hideki Yukawa, but rather heavy electrons, which are today known as muons.

This realization demonstrated that Italian cosmic ray research remained world-class despite the destruction of the war. During the same period, Edoardo Amaldi and a young Giuseppe Fidecaro set up a large apparatus with 140 Geiger counters to study mesotron interactions directly. Atop the mountains at the Testa Grigia laboratory in the Alps, researchers pushed forward with high-altitude observations, supported by institutional leaders such as Gustavo Colonnetti, the anti-fascist mathematician who became president of the CNR in 1945.

Building the Institutional Pillars of European Collaboration

Colonnetti worked tirelessly to rebuild Italian research by forging partnerships between the state and universities. Under his leadership, the CNR established specialized research centers in Rome, Padua, and Turin. On August 8, 1951, Colonnetti signed the decree formally establishing the Italian National Institute of Nuclear Physics (INFN), naming Bernardini as its first president. Shortly afterward, a founding section in Milan joined the network, cementing a national framework for nuclear research.

Simultaneously, international diplomacy was laying the groundwork for a unified European laboratory. During the UNESCO General Assembly held in Florence in June 1950, American Nobel laureate Isidor Rabi introduced a resolution urging nations to cooperate on regional research centers equipped with instruments too expensive for any single country to build alone. Pierre Auger, Director of UNESCO’s Department of Natural Sciences, and Edoardo Amaldi seized the momentum, traveling across Europe to rally skeptical physicists and hesitant politicians.

From Post-War Scarcity to World-Class Discoveries

Despite resistance from prominent figures like Niels Bohr and James Chadwick, who questioned whether a shattered Europe could build a major laboratory from scratch, the intergovernmental conference in February 1952 successfully established the provisional organization that became CERN. Edoardo Amaldi served as its first secretary-general, managing assets that briefly belonged to him alone during the transition to a permanent organization in September 1954.

With large accelerators taking shape in Geneva, including the 600 MeV synchrocyclotron completed in 1957 and the 24 GeV proton synchrotron launched two years later, European science entered a golden age. Giuseppe Fidecaro, who moved to CERN after years of collaboration with Amaldi, led an experiment in 1958 that verified the universal theory of weak interactions by observing the rare decay of pions into electrons. That breakthrough, announced to the world in Geneva, confirmed the theoretical predictions of particle physics and cemented CERN’s status as a global hub for discovery.

The research was published in Conference of the National Academy of Lincei and National Research Council - 100 Years of Collaboration for the Progress of Science, Rome, 17-18 October 2023.