The highly successful standard model of particle physics is formulated as a quantum field theory. Analytic calculations in the QFT framework are typically realized as a perturbation expansion, in which one starts from a theory of free particles and systematically computes corrections in increasing powers of an interaction parameter. Straightforward application of the algorithm yields numerous divergent terms; to make sense of them, one needs to regularize them in a subtle way that ultimately allows for a physical limit to be taken.

In 1971 a new method—dimensional regularization—was proposed; within a year it was fully established. Dimensional regularization was the essential tool for the revolution inin the early 1970s—a revolution that led to theManythough, are unaware that the origin of the regularization scheme was in Latin America, specifically in La Plata, Argentina. The story of the Argentine contribution is a fascinating one. We will tell it with a minimum of technical detail, though for interested readers we sketch thebackground inand

The international physics community reacted promptly. A total of 192 renownedincluding six Nobel laureates and eight more who would later receive Nobels, signed a public letter of protest sent to Onganía. The regime ignored that letter, but four ex-UBA physics professors—among them Bollini and Giambiagi—published in the newspapera Spanish translation, which they felt compelled to bring to the public’s attention. The online version of this article includes, in which they point out that 69 of the 75 professors andof the School of Exact and Natural Sciences had resigned because of the government’s intervention.

The rector of UBA, Hilario Fernández Long, expressed his opposition to the military dictatorship and its violation of the constitution. The regime gave him and the deans 48 hours to accept the new rules. That evening, the university council and additional professors met at a building in the School of Exact and Natural Sciences, which included the departments of biology, geology, chemistry, mathematics, and physics. The expanded council and dean Rolando García firmly agreed to reject the new rules and to spend the night in the building. The federal police invaded the building that night—before the 48-hour deadline had expired—beat up everybody they found, and destroyed laboratories and libraries, even though the university personnel put up no resistance other than to lock the doors. That event is known as, or the night of the long billy clubs. Four hundred professors and students were arrested; some of them are shown in figure. Among the arrested was Warren Ambrose, an MIT professor of mathematics and visiting professor at UBA. He wrote an account of the invasion in a letter to the, published on 3 August under the title “Short minds, long sticks.”

On 28 June 1966, a coup d’état in Argentina brought General Juan Carlos Onganía to power; having overthrown President Arturo Illia, he declared his ambition to rule for 40 years. Once in power, Onganía immediately dissolved the parliament and forbade activities of political parties. His next target was the universities: He canceled university autonomy, dissolved the elected councils integral to the decision-making process, and banned student centers. University control was given to the deans and rectors, who were subject to the Ministry of Education. The goal was to cleanse the universities of “subversives,” as defined by the military regime; avant-garde art, for example, was declared immoral.

In the 1960s Giambiagi started a long-term collaboration with Carlos Guido Bollini; the two of them are shown together in figure. Both were mathematically orientedat UBA (Bollini also had a background in nuclear energy), and both had established international contacts during stays in England. They were especially interested in particle-physics applications of mathematical objects called distributions or generalized functions. Unlike ordinary functions, which assign a value to a given argument, generalized functions are only well defined under an integral; by far the best-known example is the Diracfunction. The two colleagues thoroughly studied the books by Russian mathematicians Israel Gelfand and Georgiy Shilov, especially the first volume of their five-volume work(Academic Press, 1964). Even in his old age, Giambiagi called that book his bible; he knew many formulae and their derivations by heart and remained convinced that distributions had great potential as a tool for

The autonomy system did not just increase the academic quality of the universities. It also boosted cultural freedom and creativity, and the benefits accrued to the university had a corresponding impact in the larger society. Thanks in part to university autonomy, Argentina in the 1950s and early 1960s enjoyed a golden age in many features of its culture. One was science, particularly at the physics department at UBA. A key person responsible for that remarkable development was a young professor named Juan José Giambiagi,who was the head of the department from 1957 to 1966. Under his direction the department expanded, gained worldwide reputation, and attracted highly motivated students. Among them was Miguel Virasoro, a pioneer inperhaps best known for the so-called Virasoro algebra used inand for directing the International Centre forPhysics in Trieste, Italy, during 1995–2002.

For much of the 20th century, Argentine universities benefited from their status as autonomous institutions. Autonomy meant that the universities were independent of external powers—in particular the government and the Catholic Church—when making decisions on issues related to academics, organization, finance, and more. Such decisions were usually based on the recommendations of an elected council comprising mostly professors but also other university employees and students. The events leading to the autonomy system began in earnest in 1918, two years after democracy was established in Argentina, when students at the National University of Córdoba demanded educational reforms. Later that year those reforms were adopted at Córdoba, and the concepts advanced by the university students soon spread all over the country, notably to the University of Buenos Aires (UBA), and to numerous other Latin American countries.

Also in 1973, Harald Fritzsch, Murray Gell-Mann, and Heinrich Leutwyler described the “several advantages” of another Yang–Millsquantum chromodynamics, with its quarks and force-carrying gluons.The so-called asymptotic freedom of thewas understood in the same year, an insight that led to a perfectly consistent picture of the hadronic world of protons, neutrons, and other particles built from quarks and gluons. Thus theofwas established. In July 2012 two collaborations working at CERN found the final ingredient predicted by thethe Higgs particle. (For additional history and details, see September 2012, pages 12 and 14 ; and December 2013, pages 10 and 28 .)

Dimensional regularization precipitated a revolution in particle physics. We’ve already noted that ’t Hooft and Veltman used it to show how to make sense of the unified electroweak theory. In 1973 scientists at CERN observed a key new phenomenon, known in the field as neutral weak current, that had been predicted by that unified model; later researchers found the theory’s three massive force-carrying gauge bosons.

The ’t Hooft and Veltman paper was the first of the three dimensional-regularization works to be published, due to its swift editorial processing, even though it was the last to be submitted. It is generally viewed as an independent accomplishment, realized a little later than the work from Argentina but much more comprehensive. It is noteworthy, however, that ’t Hooft and Veltman quoted the preprint from La Plata and that Veltman was a member of the advisory editorial board ofwhen Bollini and Giambiagi submitted their first paper. Nevertheless, Veltman later wrote that he had seen the preprints from La Plata for the first time in March 1972, when he received them in a letter from Bollini and Giambiagi. At the time, he was working on the revision of his article with ’t Hooft.He further claimed that ’t Hooft and he had expressed the idea of dimensional regularization previously, citing section 5 from an earlier work of ’t Hooft onHowever, that section addressed only an extension to five dimensions.

On 21 February, three days after Bollini and Giambiagi’s manuscript arrived at, Gerard ’t Hooft at Utrecht University in the Netherlands and his PhD adviser, Martinus Veltman, submitted an article describing dimensional regularization to, another Elsevier journal. The ’t Hooft and Veltman work was more extensive, and it contained applications to so-called Yang–Millssuch as the one that unifies the weak and electromagnetic interactions. Importantly, ’t Hooft and Veltman showed that suchcould be successfully renormalized via dimensional regularization—a technical way of saying that finite physical quantities can be derived despite the divergent integrals that arise in the(Figureshows the two scientists, who received the 1999 Nobel Prize in Physics.) Their articlewas published swiftly, on 1 July. About a month later, the original work by Bollini and Giambiagi finally appearedin

Following that rejection, Bollini and Giambiagi wrote another article presenting their new approach. The second paper was more extensive and included applications toin particular, they demonstrated that dimensional regularization preserves the gauge invariance ofa crucial criterion for a regularization scheme (see boxfor a review ofThey sent the new work to the Italian journal, where it arrived on 18 February 1972. It was accepted, but it was not published until 11 November.Meanwhile, preprints of both papers had been sent to European and North American libraries. Giambiagi was sure that they were available in the CERN library, for instance, so it seems plausible that theorists worrying about regularization would have known about that work.

Their new method—dimensional regularization—was related to a technique called analytic regularization that they had developed years earlier with Giambiagi’s PhD adviser, Alberto Domínguez. But dimensional regularization was more powerful. Bollini and Giambiagi first applied their technique to spinless particles, and in November 1971 they submitted an article to the well-respected journal, published by the Dutch house Elsevier. However, the editors and referees found the new approach too strange and blocked its publication. We were not able to retrieve a copy of the referee report, but apparently it advised the authors to stop wasting their timeand return to work in= 4.

Despite the difficult conditions, the La Plata years turned out to be Bollini and Giambiagi’s most productive period. Gifted students from UBA joined them, including Fidel Schaposnik, now a prominent leader in ArgentinianIn 1971 Bollini and Giambiagi came up with a new idea for how to make sense of the divergent integrals that arise in perturbativeTheir approach, briefly described in box, surprised manyThey calculated in= 4 +dimensions and took the limit→ 0 only at the very end.

In time, Bollini and Giambiagi moved from Buenos Aires southeast to the town of La Plata, where they worked at a smaller university from 1968 to 1976. Working conditions were not particularly good. For instance, the physics department did not even provide offices for them; instead, they installed themselves in the math department. Economic crises and political repression were ongoing, and communication with the international physics community was limited. Physics journals arrived up to 6 months late.

and its aftermath disrupted academic activities in Argentina for several decades. Due to that invasion and the subsequent repression, all deans at UBA resigned, as did 1400–1500 professors around the country; about 300 of the best scientists, Virasoro among them, left Argentina altogether.The excellent physics department at UBA fell into ruin. Bollini, Giambiagi, and other theorists continued their work away from the UBA campus, in a two-room apartment in the Colegiales neighborhood of Buenos Aires. (Figureshows Bollini and Giambiagi working together in one of the rooms.) In an ironic salute to the general whose actions forced the move from UBA, the theorists named their apartment the Juan Carlos Onganía Institute.

Escape to Brazil Section: Choose Top of page ABSTRACT End of a golden age Too strange to publish Escape to Brazil << Little mention in Stockho... I.Supplementary Material REFERENCES CITING ARTICLES

As the elements of the standard model were coming into place, the people of Argentina were experiencing hard times. In 1973 Giambiagi was interrogated by the federal police and accused of being part of a Jewish or communist conspiracy. As evidence, the police cited the relatively large number of Jewish physicists who had signed the petition sent to Onganía in 1966. However, Giambiagi successfully countered those accusations. He mentioned, for instance, the considerable funds received from the US Ford Foundation, which he had arranged when he was still head of the physics department at UBA. He then asked the authorities if they really expected that the Ford Foundation would sponsor a communist conspiracy.

4 11 11. P. H. Lewis, Guerrillas and Generals: The “Dirty War” in Argentina, Praeger , Westport, CT (2002), p. 147. See also M. E. Andersen, Dossier Secreto: Argentina’s Desaparecidos and the Myth of the “Dirty War,”, Westview Press , Boulder, CO (1993). 12 Argentine Military Believed U.S. Gave Go-Ahead for Dirty War ,” 12. National Security Archive, “,” http://www2.gwu.edu/~nsarchiv/NSAEBB/NSAEBB73/index3.htm The national situation got even worse in March 1976: Argentina suffered another military coup, this time against Isabel Perón. The new military regime instituted a national campaign—the infamous Dirty War—against political dissidents and other left-wingers. General Luciano Menéndez (seen in figure), one of the military leaders, announced “We are going to have to kill 50,000 people: 25,000 subversives, 20,000 sympathizers, and we will make 5,000 mistakes.”In April he ordered the burning of books by such authors as Gabriel García Márquez and Pablo Neruda. In June 1976 US Secretary of State Henry Kissinger visited Argentina and signaled to the generals there that the US government supported them.

To intimidate the population, the military regime made frequent arrests based on unsubstantiated accusations. Soldiers would break into and steal from houses or beat up randomly selected people on the street. During the military rule from 1976 to 1983, those who seemed suspicious to the regime could suddenly “disappear”—that is, be taken to secret prisons, tortured, and killed. The number of victims from that period is estimated to be 10 000–30 000.

The military leaders generally viewed intellectual activities with distrust. They dispatched spies to systematically infiltrate the universities and identify students or professors with critical views; those so identified were in danger of disappearing. Even using such terms as “bourgeoisie” was sufficient to arouse suspicion. The University of La Plata was among the institutions affected. In 1976 Giambiagi was again interrogated by the federal police. The incident must have been very aggressive and frightening; in any case, soon afterward he and his family decided to flee Argentina and escaped to Rio de Janeiro, Brazil. They traveled by land to avoid airport controls. In the following year, Bollini’s home was invaded by federal police, who threatened his family as they searched for evidence that he was involved with a communist conspiracy. Finding none, they contented themselves with stealing items from the house. The Bollini family, too, decided to escape to Rio de Janeiro.

Before long, the two physicists were working at the Centro Brasileiro de Pesquisas Físicas (CBPF; Brazilian Center for Research in Physics). Giambiagi was the head of the center’s particle-physics department from 1978 to 1985. One year after that term ended, he became director of the Centro Latino-Americano de Física (CLAF), which he had founded back in 1960 with two prominent colleagues: José Leite Lopes from Brazil and Marcos Moshinsky from Mexico. Giambiagi encouraged interested young scientists at CLAF to address subjects of practical relevance, such as energy resources and climate.

Brazil had its own right-wing military regime from 1964 to 1985, though it was somewhat less cruel than those in Argentina, Chile, and Uruguay. It tolerated Bollini and Giambiagi, but other scientists in Brazil did get in trouble for their alleged involvement with communist conspiracies. In particular, Leite Lopes, perhaps Brazil’s most important theoretical physicist, was forced to vacate his position in 1969. He left Brazil for France, where he became a professor at the Louis Pasteur University in Strasbourg; he returned to Brazil in 1986.