CoLet's divide the article From slow neutrons to quarks, a story leading to the physicist "ruling chaos", published in the newspaper The sun 24 hours of 31 October.
The text, written by Fulvio Ananasso, president of the States General of Innovation, e Piero Sammartino, celebrate the recent Nobel Prize to the Italian physicist Giorgio Parisi and the importance of Italian physics and its protagonists in history, from Marconi to Fermi, from Emilio Segrè to Carlo Rubbia, from Riccardo Giacconi up to the present day.
«The Nobel Prize to Giorgio Parisi underlines the relevance of Italian Physics - explain the authors - and shows how this branch of Science is increasingly assuming a central role in our own existence, think of the climate, migratory phenomena, civil coexistence to the pursuit of peace". Below is the complete article.
From slow neutrons to quarks, a story leading to the physicist "ruling chaos"
Nobel 2021. This year's prize to Giorgio Parisi is the last in a series of six, from Marconi to Giacconi, and represents a recognition of the great tradition of
Roman School of Physics, which dates back to Enrico Fermi and the boys of via Panisperna.
After Guglielmo Marconi in 1909, Enrico Fermi in 1938, Emilio Segrè in 1959, Carlo Rubbia in 1984 and Riccardo Giacconi in 2002, the Nobel Prize for Physics was awarded this year to our George Parisi (“the physicist who dominates chaos”), Emeritus Professor of Theoretical Physics at the University of Rome La Sapienza and President of the Accademia Nazionale dei Lincei. Beyond the prestigious recognition, the Faculty of Physics at La Sapienza has distant roots, and has generated great minds over time, starting with Enrico Fermi with his "boys from via Panisperna" (including Edoardo Amaldi). The Roman School of Physics has realistically laid the foundations and indicated the direction for the great achievements of Italian Physics in the world.
From the discovery of the neutron (Chadwick, 1932) to the atomic pile of Chicago (1942), the figure of Enrico Fermi dominates the international field by proposing a first interpretation of the "weak interaction", then with the first experiments with (slow) neutrons which cause radioactivity in 1934. Until then it was thought that the radioactivity produced by the irradiation of a material was proportional to the energy of the particles used, while Fermi discovered that the neutrons slowed down by paraffin caused an increase in radioactivity up to a hundred times greater. Fermi then continued his research arriving at the Nobel Prize in 1938, followed by the flight from Italy due to the racial laws and the creation of a new group in Chicago which will lead to the creation of the first atomic pile (December 2, 1942).
After the war, Edward Amaldi he had been the architect of the relaunch of the Roman School of Physics, taking on the legacy of Enrico Fermi who had created it and of Orso Mario Corbino who had conceived and financed it. The existence and activity of research institutes of world excellence, such as INFN or CERN, cannot be imagined without his patient and tireless determination. Even though Amaldi was the first to detect (1955) the first two revealing events of the antiproton on a photographic emulsion, he preferred caution and was overtaken in the race for the Nobel by his friend Emilio Segrè, who, while achieving the experimental results on proton annihilation -antiproton while he had already been in the USA for some time, he too came from the group of boys from via Panisperna together with Fermi and Rasetti, who was his supervisor and with Amaldi himself participated in the pioneering first experiments on slow neutrons.
Charles Rubbia, Nobel 1984 for the discovery of intermediate vector bosons, discussed his thesis on cosmic rays in Pisa with the supervisor Marcello Converti, the very young Roman researcher who in 1943, after the bombing of San Lorenzo and the damage suffered by the nearby Institute of Chemistry, loaded his instruments onto a cart (the young Amaldi preceded him on his bicycle to guide it) to save them in the basements of the high school Virgilio in via Giulia, contiguous to the Vatican and where it was therefore hoped there would be no bombings. And the experiment of Conversi, Pancini and Piccioni, although carried out in very precarious conditions, is universally recognized as the progenitor of particle physics of the 1900s. We owe them – who never received the Nobel Prize – the discovery of the “muon”, which together with the subsequent discovery of the “pion” will give rise to High Energy Physics.
Richard Giacconi, now also a naturalized American, received the Nobel Prize in 2002 for pioneering contributions to Astrophysics with the discovery of X-ray sources of cosmic origin. But on closer inspection, his research comes from the studies on cosmic rays with Giuseppe Occhialini at the University of Milan and from those with Bruno Rossi, with whom he designed detection instruments for the development of research on X-rays.
AND Giuseppe Occhialini is another great Nobel failure. He studied Physics in Arcetri, where Enrico Persico, a friend of Fermi, taught and they also worked Gilberto Bernardini And Bruno Reds. And it was in Arcetri that he learned from Bruno Rossi a technique that he would use in England at the Cavendish Laboratory, a Geiger counter suitable for detecting positrons in a 'cloud chamber' conceived by his collaborator Blackett. After a long parenthesis in Brazil in the last years of fascism, he returned to England in 1944 and together with the director of the Wills Physics Laboratory in Bristol he studied cosmic rays again with his new technique based on traces in photographic emulsions. Thus the "pion" (Yukawa particle) is discovered which will allow the understanding of the "strong interaction". But the Nobels will go to Blackett (who, however, will immediately acknowledge his debt to Occhialini) for the discovery of the "positron" (1948) and to Powell for the discovery of the "pion" (1950). Despite many other contributions to particle physics, Occhialini will not receive the Nobel, and it is now known that his name had been vetoed for not wanting to collaborate on the "Manhattan Project" on the atomic bomb.
Among those who might have deserved the Nobel without ever getting it, a special mention goes to the great Nicholas Cabibbo, one of the best known Italian physicists in the world together with the equally great Tullio Regge, for the contribution given to the knowledge of the world of elementary particles. Cabibbo's theories (who worked at CERN in Geneva and at the Universities of Rome La Sapienza and Tor Vergata) are present in all books on Quantum Physics, having obtained important scientific results in the field of particle physics, studying and formulating them in 1963 the theory of the weak interaction, introducing the so-called Cabibbo angle. In 1973 Makoto Kobayashi and Toshihide Maskawa (both awarded the Nobel Prize for Physics in 2008) proposed a multidimensional generalization of the model of the #39;Cabibbo angle, from which it was possible to predict some characteristics of the "quarks".
In short, Italian Physics represents a national pride to be valued and proud of.
A key to addressing complexity
Physics. Beyond the theory
Following the awarding of the Nobel Prize to Giorgio Parisi, one perceives how the media and the general public are increasingly aware of the extraordinary importance of Italian research in the field of Physics. A Physics that begins to establish itself even among non-experts (one of the authors is an engineer, the other a physics teacher, a fellow student of Parisi) in its increasingly central role with respect to the very life of mankind on the planet - climate , migratory phenomena, civil coexistence, pursuit of peace, etc. A Physics that appears to go beyond the confines that relegated it to an abstract subject of study for scientists, allowing one to question the fundamentals of the Universe, but becoming more and more an enabling discipline for a number of innovative sectors of our daily life, above all through the digital transformation, which underlines the complexity of the world we live in.
Alongside the name of Giorgio Parisi, it is pleasing to see reports on Fabiola Gianotti, reconfirmed as director of CERN in Geneva, or Anna Grassellino, co-director of FermiLab in Chicago, and many/the others more or less known, who underline the history and relevance World Championship of Italian Physics.
After the discovery of slow neutrons in the fish tank in via Panisperna which earned Enrico Fermi the Nobel prize, the contribution in High Energy Physics with particles from cosmic rays (in high mountain laboratories, to reduce the atmospheric layer crossed from particles) or subsequently powerful accelerators, as adequate economic resources became available after the post-war reconstruction.
Luis Alvarez, Nobel Prize 1968, wrote: "Modern particle physics began during the last days of the Second World War, when a group of young Italians, Conversi, Pancini and Piccioni, began a remarkable experiment" (existence of the "muon" , then called a “mesotron,” NDS).
In addition to cosmic rays, however, machines capable of accelerating particles to very high energies were needed, and Edoardo Amaldi first and Gilberto Bernardini then promoted the construction of a powerful accelerator for electrons, the synchrotron - existing at the time only in the USA at Caltech in Pasadena and Cornell of Ithaca (NY) -, made in 1958 by Giorgio Salvini.
The formation of a generation of physicists passes through the Frascati synchrotron, the forerunner of those modern mammoth accelerators whose progenitor was the Accumulation Ring (AdA,1961) of the Frascati Laboratories, which was then brought to France and generated the Ring of Double Energy (ACO). Only in 1973 was the Spear ring activated at Stanford, while in the 1980s the SPS ring at CERN allowed Carlo Rubbia to reveal the intermediate boson vectors in a proton–antiproton collision process and thus unify the weak interaction with the electromagnetic.
We should still talk about the Gran Sasso Laboratories, built in a few years for experiments in conditions of cosmic silence – eg neutrinos. We should talk about many other leading physicists and several other important experimental projects and initiatives, including the latest by Edoardo Amaldi for the detection of gravitational waves. Traces of this and many other useful information can be found in "Physics in the Italian culture of the twentieth century" (Laterza, 1996) by the physicist Carlo Bernardini, who collaborated with Bruno Touschek in the creation of AdA and left us in 2018, remaining in the heart of many of his students and colleagues who were able to appreciate his work and human qualities.
