Cesare Mansueto Giulio Lattes 1924-2005
Cesare Mansueto Giulio Lattes, one of the pioneers of the pion discovery, died on 8 March 2005 at Campinas, São Paulo State, Brazil.
Born in Curitiba, Brazil, Lattes studied at São Paulo University, where he was a student of Giuseppe Occhialini, graduating in 1943. In 1946 he joined Occhialini in Cecil Powell's group at the University of Bristol, where together with Hugh Muirhead they made the historic discovery of the pion in studies of cosmic rays (CERN Courier October 1987 p11). At the end of 1947 Lattes moved to Berkeley to work with Eugene Gardner at the 184 inch cyclotron, where, in Lattes' own words: "The beam of α-particles was only 380 MeV (95 MeV/nucleon), an energy insufficient for producing pions. I took my chance on the 'favourable' collisions in which the internal momentum of a nucleon in the a and the momentum of the beam provided sufficient energy in the centre-of-mass system." The method proved successful and produced both positive and negative pions. Later, around February 1949, just before leaving the US, Lattes was asked by Edwin McMillan to look at some plates exposed to gamma-rays from the 300 MeV electron synchrotron, and found a dozen pions of both charges, surely the first artificial photoproduced pions ever detected.
Despite many invitations to join research institutions in other countries, Lattes returned to Brazil in 1949 to take part in the establishment of a Brazilian Center for Research in Physics (CBPF). His international prestige attracted many well known researchers to the institution, which also benefited from the contributions of other prominent scientists such as Gert Molière, Léon Rosenfeld and Richard Feynmann. Lattes was scientific director from the centre's foundation until 1955, after which, from 1955 to 1957, he served as a research associate at the universities of Chicago and Minnesota. He was also a visiting professor from 1964 to 1965 in Pisa, where he became interested in geochronology research.
Meanwhile, in 1947, Lattes had found out at Bristol's Department of Geography that there was a meteorological station 5500 m above sea level on Mount Chacaltaya in Bolivia, which was easily reachable by car. There he exposed borax-loaded emulsion plates to cosmic rays and obtained a mass for the pion. Lattes always said the observation of the pion was facilitated by both the borax-loaded emulsion plates and Mount Chacaltaya, the true discoveries concerned. In the 1950s he constructed an observatory at Chacaltaya, with a budget obtained with some difficulty from the National Council of Technological and Scientific Development (CNPq).
In 1958 Hideki Yukawa wrote to Lattes to propose uniting the efforts of Japanese and Brazilian cosmic-ray groups in order to study multiple meson production at the Mount Chacaltaya Observatory. The Brazil-Japan Collaboration on Cosmic Rays in Chacaltaya Emulsion Chamber Experiments (the B-J Collaboration) began in 1962. The work of the B-J Collaboration was appreciated by the international community, particularly at CERN where the proposal for the UA1 experiment by Carlo Rubbia mentions the collaboration's observation of "fire-balls". The so-called Centauro events, also observed by the collaboration, are still under study in both cosmic-ray and accelerator experiments.
In 1967 Lattes joined the State University of Campinas (UNICAMP) in São Paulo State, where he started the Institute of Physics, with its first research laboratory dedicated to studies of geochronology and cosmic rays through inexpensive experiments. This was one of Lattes' characteristics: he had a profound faith that the real facts of nature are observable even with inexpensive experiments, a lesson he learned early as a student at São Paulo University. Today UNICAMP is one of the most important institutions in Brazil.
Lattes received many awards from South American countries, as well as the 1987 Physics Award from the Third World Academy of Sciences. Probably the most important reward to him, however, was the recognition of the Brazilian scientific community of his enthusiasm for modern science in Brazil, which nowadays accounts for 1% of the world's scientific research, despite the still small number of Brazilian scientists and some modest budgets. The discovery of the pion brought attention to the role of science in Brazil, where the scientific community's debt to Lattes has been recognized by the CNPq through its database of researchers' curricula in all areas of knowledge, the "Plataforma Lattes".