Nicola Cabibbo
Born	(1935-04-10)10 April 1935 Rome, Italy
Died	16 August 2010(2010-08-16) (aged 75) Rome, Italy
Nationality	Italian
Fields	Particle physics
Institutions	Italian National Institute of Nuclear Physics Pontifical Academy of Sciences
Known for	Cabibbo angle

Nicola Cabibbo (10 April 1935 – 16 August 2010^[1]) was an Italian physicist, best known for his work on the weak interaction. He was also the president of the Italian National Institute of Nuclear Physics from 1983 to 1992, and from 1993 until his death he was the president of the Pontifical Academy of Sciences.^[2] He was born in Rome.

Work[link]

The Cabibbo angle represents the rotation of the mass eigenstate vector space formed by the mass eigenstates Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle{| d \rangle , \ | s \rangle}

into the weak eigenstate vector space formed by the weak eigenstates Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle{| d^\prime \rangle , \ | s^\prime \rangle}

. The rotation angle is θ_C = 13.04°.

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

• The transitions between up and down quarks, between electrons and electron neutrinos, and between muons and muon neutrinos had similar likelihood of occurring (similar amplitudes); and
• The transitions with change in strangeness had amplitudes equal to one fourth 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. Modern measurements show that θ_C = 13.04°.

Before the discovery of the third generation of quarks, 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 had bitter feelings that the Nobel Prize committee failed to reward Cabibbo for his part.^[3] Asked for a reaction on the prize, Cabibbo preferred to give no comment. According to sources close to him, he was very embittered.^[4]

Recent work on evaluating the importance of scientific papers using Google's PageRank algorithm identifies Cabibbo's paper "Unitary symmetry and leptonic decays"^[5] as the top ranked out of 353,268 articles published by the American Physical Society since 1893 in journals such as Physical Review Letters.^[6] The same research shows that most of the authors of the top-ranked papers are also Nobel Prize winners, which makes Cabibbo's exclusion seem all the more curious.

Later, Cabibbo researched applications of supercomputers to address problems in modern physics with the experiments APE 100 and APE 1000.

Cabibbo supported attempts to rehabilitate executed Italian philosopher Giordano Bruno, citing the apologies on Galileo Galilei as a possible model to correct the historical wrongs done by the Church.^[7]

After his death in 2011, the Franklin Institute awarded him with the Benjamin Franklin Medal in Physics.^[8]

Death[link]

He died from respiratory problems in a Rome hospital on August 16, 2010 at the age of 75.

References[link]

External links[link]

Wikiquote has a collection of quotations related to: Nicola Cabibbo

• Cabibbo biography from the Istituto e Museo di Storia della Scienza (Italian)
• Parisi, Giorgio (2011). "Nicola Cabibbo". Physics Today 64: 59. Bibcode 2011PhT....64b..59P. DOI:10.1063/1.3554322. 

Luciano Maiani

Luciano Maiani (born 16 July 1941 in Rome) is a San Marino citizen physicist best known for his prediction of the charm quark with Sheldon Lee Glashow and John Iliopoulos (the "GIM mechanism").

Academic history[link]

In 1964 Luciano Maiani received his degree in physics and he became a research associate at the Istituto Superiore di Sanità in Italy. During that same year he collaborated with R. Gatto's Theoretical Physics group at the University of Florence. He crossed the pond in 1969 to do a post-doctoral fellowship at Harvard's Lyman Laboratory of Physics. In 1976 Maiani became a Professor of Theoretical Physics at the University of Rome, however he traveled widely during this period, holding visiting professorships at the Ecole Normale Supérieure of Paris (1977) and CERN (1979–1980 and 1985–1986). Maiani also took an interest in the direction of particle physics research start on CERN's Scientific Policy Committee from 1984 to 1991. Then in 1993 he became President of Italy's Istituto Nazionale di Fisica Nucleare (INFN). From 1993 to 1996 Maiani served as a scientific delegate in CERN Council and then as that council's president in 1997. Thereafter he became Director General of CERN, serving from 1 January 1999 through the end of 2003. From 1995-1997 Maiani chaired the Italian Comitato Tecnico Scientifico, Fondo Ricerca Applicata. At the end of 2007 he was proposed as President of Consiglio Nazionale delle Ricerche, but his nomination was suspended temporally after he signed a letter criticizing the rector of 'La Sapienza' University in Rome, who invited the Pope Benedict XVI to give a Lectio Magistralis in 2008.^[1] However he became the President of CNR since 2008.

Luciano Maiani has authored over 100 scientific publications on the theory of elementary particles often with several co-authors. In 1970 he predicted the charmed quark in a paper with Glashow and Iliopoulos which was later discovered at SLAC and Brookhaven in 1974 and led to a Nobel for the discoverers. Working with Guido Altarelli in 1974 they explained that the observed octet enhancement in weak non-leptonic decays was due to a leading gluon exchange effect in quantum chromodynamics. They later extended this effect to describe the weak non-leptonic decays of charm and bottom quarks as well and also produced a parton model description of heavy flavor weak decays. In 1976 Maiani analyzed the of CP violation in the six-quark theory and predicted the very small electric dipole moment of the neutron. In the 1980s he started using the numerical simulation of lattice QCD and this led to the first prediction of the decay constant of pseudoscalar charmed mesons and of B mesons. A proponent of Supersymmetry, Maiani once said that the search for it was "primary goal of modern particle physics".^[2] He has not confined his interest to the theoretical side of physics either, with involvement in ALPI, EUROBALL, DAFNE, VIRGO and the LHC.

Awards[link]

• 1979 Matteucci Medal, Accademia Nazionale dei XL
• 1987 Sakurai Prize of the American Physical Society
• 1996 Doctor honoris causa, Université de la Méditerranée, Aix-Marseille
• 2007 Dirac Medal, Abdus Salam International Centre for Theoretical Physics, Trieste, Italy
• 2010 Doctor honoris causa, Benemérita Universidad Autónoma de Puebla, Puebla, México

See also[link]

• GIM mechanism

References[link]

• Professor Luciano Maiani is chosen as next Director General of CERN (19 Dec 1997)
• S. L. Glashow, J. Iliopoulos, and L. Maiani, Phys. Rev. D2, 1285 (1970)