Nicola Cabibbo (1935-2010)

 

Nicola Cabibbo, one of the most important theoretical physicists of our time, died of cancer in Rome on 16 August, 2010 at the age of 75.

 

Before the discovery of quarks, he gave the correct formulation of the weak current couplings that in modern terms corresponds to the phenomenon of quark mixing. His formulation, in terms of the famous Cabibbo angle, was later extended to three families of fermions (and more recently also applied to neutrino mixing), and plays an essential role in the Standard Model of fundamental interactions.

Over the years he applied his extremely lucid, deep and flexible mind to a wide range of problems, also including experiments, such as the measurement in 1963 of the electron helicity in muon decay, and the conception and design of the parallel computers APE, which he developed, starting in the early 1980s, for the simulation of the QCD theory of the strong interactions on discrete space-time.

Highly respected for his broad range of competence, international recognition, and political and managerial skills, he was appointed to important positions in Italy: he was President of INFN from 1983 to 1992 and President of ENEA, the Italian energy agency, from 1993 to 1998.

Since 1993 he had been President of the Pontifical Academy of Sciences. During practically all of his scientific career he was a Professor in Rome, where he was a leading actor in making the theory group one of the most reputed ones in Europe. Outstanding theorists like Parisi, Testa, Petronzio and Martinelli were among his students. Altarelli and Maiani were among his younger collaborators in the 1970s.

Throughout his life he had a continuous connection with CERN, and his most famous work, the 1963 paper on mixing, shows CERN as his affiliation. He was later a member of the SPC and of the Council and visited CERN regularly.

Recently, in 2004, he spent a year at CERN as guest professor. Free from non-scientific burdens, with youthful enthusiasm he plunged back into current research, joined the NA48 collaboration and, among other contributions, quantitatively explained an intriguing feature of the data in K-> 3pi decay in terms of the final state pi-pi interaction computable from chiral symmetry theory.

Nicola Cabibbo will be sorely missed by all those who had the chance to work with him and to appreciate directly his outstanding qualities as a person and as a physicist.