Nicola Cabibbo

Nicola Cabibbo (born 10 April 1935) is an Italian physicist, best known for work on the weak nuclear interaction. He was also the president of the Italian National Institute of Nuclear Physics from 1983 to 1992, and since 1993 he has been the president of the Pontifical Academy of Sciences.

Cabibbo's major work on the weak nuclear interaction originated from a need to explain two observed phenomena:

1. the transitions between up and down quarks, between electrons and electron neutrinos, and between muons and muon neutrinos had similar amplitudes; and
2. the transitions with change in strangeness had amplitudes equal to 1/4 of those with no change in strangeness.

Cabibbo solved the first issue by postulating weak universality, which involves a similarity in the weak interaction coupling strength between different generations of particles. He solved the second issue with a mixing angle θ_c, now called the Cabibbo angle, between the down and strange quarks.

Before the discovery of the third generation of quarks (1973), Cabibbo's work was extended by Makoto Kobayashi and Toshihide Maskawa to the Cabibbo-Kobayashi-Maskawa matrix. In 2008, Kobayashi and Maskawa shared one half of the Nobel Prize in Physics for their work. Some physicists, especially Italian, had bitter feelings that the Nobel Prize committee failed to reward Cabibbo for his part. Asked for a reaction on the prize, Cabibbo preferred to give no comment. According to sources close to him, he was very embittered.

More recently, Cabibbo has been researching applications of supercomputers to address problems in modern physics with the experiments APE 100 and APE 1000.

External links

• Unitary Symmetry and Leptonic Decays, Cabibbo, Physical Review Letters 10, 531-533 (1963)
• Cabibbo biography from the Instituto e Museo di Storia della Scienza (in Italian)

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