Cabibbo passed away


This is the kind of news I would not have wanted to write about in my blog. Nicola Cabibbo died yesterday at the Fatebenefratelli Hospital in Rome. He was fighting with a long time illness. Cabibbo has to be considered, for very good reasons, one of the greatest Italian physicists. He is the product of the Roman school of physics that started its glorious traditions with Enrico Fermi. One of his teachers was Edoardo Amaldi, one of the boys of via Panisperna that, together with Fermi, brought Italian physics to a worldwide level. By himself, he contributed to a formidable group of physicists working at the University “La Sapienza” in Rome that gave fundamental contributions to our current understanding of the Standard Model.

Last time I have heard a talk by him was at Accademia dei Lincei last year (see here). It was exciting to hear directly from his voice a layman description of his most fundamental discovery. I did not think that would have been the last time I would have seen him. He has been my teacher at “La Sapienza” when I was studying to get my “laurea” in physics. He firstly exposed me to quantum field theory and so I  learned how to compute the first correction (the Schwinger’s one) of the magnetic moment of the electron. His exposition was always very clear and he made things so easy to understand that this first course is yet a formidable basis to build upon for my career as a physicist. Finally, he was my supervisor for my laurea’s thesis and he was instrumental for me to reach the highest honors in my final examination.

Cabibbo was the president of the Pontificia Accademia delle Scienze as he was a Catholic and he supported his faith in different occasions. One of this was the discussion with Penzias about faith and science organized by Riccardo Chiaberge, an Italian journalist (see here).  The crucial point of his thought was that, as believers, there is no reason to fear science as God may have decided any kind of avenues to pursue His aims.

His dead has been a bad news for me and I think that, behind the sorrow, we will greatly miss him for the clearity of his thought and the excitement he always transmitted about science, this kind of excitement that he also gave to me, one of his students.

Note: Cabibbo was awarded this year with the Dirac medal by ICTP (see here and here).


Cabibbo and quark mixing


Today I have been at Accademia dei Lincei, a renowned institution located here in Rome. There was a talk by Nicola Cabibbo about quark mixing. This conference was addressed also to people not having a proper knowledge of physics, making quite exciting to listen. Cabibbo is member of the Accademia since 1973 and his groundbreaking discovery happened in 1963 (see here). There has been some fuss last year with Nobel prize awarded to Kobayashi and Maskawa but not to Cabibbo (see my post here). So, it was a chance to hear from his voice his personal recollections about all this matter.

He gave a historical overview about quark mixing and how he found himself on the right path. Then, he cited when, on 1963, he met Feynman that said him that things could not work as he got V+A in some cases rather than V-A. Indeed, confirmations arrived later.

Giorgio Salvini, an experimental physicist well-known for his contributions to high-energy physics, introduced Cabibbo recalling as, when in Frascati, after Kobayashi and Maskawa got published their paper, he hit his forehead saying “How did not I think about six quarks?”. Indeed, Cabibbo recalled when, in the sixties, he was in his office at Rome University “La Sapienza” and Shelly Glashow knocked on his door. Glashow asked to Cabibbo if his approach could be used to understand CP violation. At that time, Glashow was frequently in Rome and, some time after, he took Luciano Maiani with himself at Harvard and we all know as history went. To obtain CP violation from Cabibbo mechanism one should introduce a complex phase factor. At that time no more than four quarks were postulated. So, Cabibbo answered that was not possible as, whatever phase one introduces, this can be removed. With six quarks this is no more possible and so, he said, having not thought about six quarks, he missed in this way the possibility to uncover the full CKM matrix.

In the end of the conference, some questions were put forward and Cabibbo promised to put all the talk on paper, after Giorgio Salvini solicited him for doing this. I hope to read his paper. This is a must after such a beautiful talk.

Nicola Cabibbo and Arno Penzias


Today I have been at Festival della Matematica 2009 here in Rome to listen at a discussion with Arno Penzias and Nicola Cabibbo.  The moderator was festivaldellamatematica2009Riccardo Chiaberge, a journalist of the italian newspaper Il Sole 24 Ore. Chiaberge wrote a book with an interview to George Coyne and Arno Penzias (in Italian, see here). Cabibbo is currently the President of the Pontificia Accademia delle Scienze and is a believer. This evening he took the role Coyne had in the book in a confrontation between scientists with different beliefs. Asked by Chiaberge if the Pope listens Accademia, Cabibbo said “Sometime.” and cited the case of cerebral death.

Penzias has been put by Chiaberge on the Einstein side, a “non-believer deeply religious”. But what Penzias said has been sometime astonishing revealing a kind of faith elevating humankind well above its nature. Of course, themes like string theory and multiverse were also touched upon in the discussion. Cabibbo said that we should give time to the theory to develop before to conclude anything about, being now too early to draw any conclusion. Stringists will say but surely “mathematics is truly beautiful”. When he said so I thought to Perelman that, copying a functional from string theory, achieved one of the greatest goals of modern mathematics. Penzias is more skeptical about and does not think it should be considered science yet and, on the same line, multiverse is not falsifiable and so to be dismissed. Cabibbo said “till now!” letting us think that the future will deserve some surprise about as always happened in matters like these.

This point was quite entertaining as Cabibbo defended multiverse as the most elegant idea to explain the foundations of quantum mechanics but, as Chiaberge emphasized, this is an escape for atheist to claim the non-existence of God. On the other side, Penzias said that our current understanding of Universe and all this nice fine tuning of its constants appears a serious support for believers.

Galileo, Copernico and Kepler were discussed and the Galileo question, with his trial and abjure, was declared by Cabibbo as a severe error by the Catholic Church that cost too much to Italian science. He said that “Bellarmino, notwithstanding was a fine cultured man, failed to recognize that these were completely new matters” and should have been carefully treated.

About the question of intelligent design and Darwinism, Penzias put forward a nice metaphor. He remembered the last scene of The Wizard of Oz where a dog moves a curtain unveiling the wizard pushing around buttons all the time and this appears to be the god of intelligent design. On the other side, human beings are really cousins of chimpanzees but there is something more, that kind of inexplicable that makes us believe that something like love and free will are real as the rest of our physical world. Cabibbo added that the idea of evolution should enter into the certainties accepted by the Catholic Church as the Copernican system and all that. Evolution is an assessed fact but still some embarrassment is seen from clerics, the same that happens when one talks about the possibility of intelligent life in other solar systems. Giordano Bruno has not been fully digested by Catholic Church yet.

Cabibbo also put forward a nice analogy between phase transitions and the appearance of  intelligence in human beings that completely overwhelmed previous animal species, a threshold effect.

Chiaberge gave a nice summary of the discussion by saying:”Science has limits but no authority should impose limits on it”. All agreed about this but Penzias remembered horrors of some experiments and Cabibbo emphasized that for medicine some kind of limits should be eventually considered or, better, self-imposed.

Tomorrow I will be there to listen Edward Witten. Stay tuned!

Nicola Cabibbo and the Nobel prize


Nicola Cabibbo has been a teacher of mine at University “La Sapienza” in Rome. He taught me quantum field theory and I firstly got exposed to this beautiful construction of human mind through his wonderful lessons. I still have a vivid recollection of these lectures in the same room where Marcello Conversi explained us a lot of phenomenology ranging from blackbody radiation to Fermi theory of beta decay. Cabibbo was also my thesis advisor and he was there when I discussed it at my final “laurea” examination. So, I have a lot of reasons to regret for a missing deserved prize to him. I have read this article on Physics World and so memories flowed down. I have met him recently at Accademia dei Lincei in Rome. That was when Sergio Ferrara come there to talk about supersymmetry (see here). Cabibbo awarded Ferrara with a medal of the Accademia and it was a very nice moment.

I should say that Cabibbo’s lectures about QFT are still in my mind and I mantain memos of them on my shelves. Anyhow, Cabibbo is part of history of physics. No prize can change this or change the role he had in the development of particle physics.

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