Physics

Last Tuesday I was in Mantova, a pleasant little town in northern Italy, rich of monuments and treasures like the Palazzo Ducale,  which hosts a vast collection of paintings and frescoes from reinassance artists. But I was not there for a private visit; I was in fact invited to comment and provide answers to questions that the audience of a movie, "The Hunt for the Higgs", were invited to ask after seeing it.

The host of the event was the "Cinema del Carbone", a small movie theater near the center of the town. The organizers called me there because they knew me from my previous participation to last years' Festivaletteratura, a literature festival which takes place yearly in September, where authors of books and other media get in touch with their public.
"We haven't the foggiest idea what drives the new high-temperature superconductors, or what makes a snowflake, or how the mind or the economy works. What is more, nothing high energy physics can do will ever be of the slightest direct help in solving these overwhelmingly hard problems"

Philip Anderson, The Case Against the SSC, 1987
(Anderson was one of the theorists who are credited for discovering the "Higgs mechanism" in the early 1960s. He is a 1977 Nobel laureate in Physics for his studies of the electron structure of magnetic systems)

Classical gravity is not good enough.  As a first step, one must think about groups since that is the foundation of the Standard Model of physics.

The top quark is the most massive elementary particle that we have so far discovered at particle accelerators. One usually describes this by saying that the top mass is about 185 times larger than the mass of a whole proton; but since the proton is a composite object, it is not the best comparison stone; I would prefer to compare the top mass to the mass of the lightest quark, which we only roughly know to be in the range of a 2 to 5 MeV. Then one gets a more dramatic picture: the up quark and the top quark are both elementary particles, but the latter is 50,000 times larger than the former. Can that be true ?

I may today perhaps make the boldest claim I ever made, at least many will think so, and I am not known for my humbleness (though I should be – how many established scientists do see themselves as merely a perverted, psychopathic robot?): The world’s first ever touchable, functioning quantum many-worlds model that can violate John Bell’s inequality even stronger than standard quantum mechanics!

In a paper appeared a few days ago on the Cornell Arxiv Campbell, Ellis and Williams discuss how the LHC experiments have a chance to obtain information on the Higgs boson width by studying four-lepton events at masses much above the 126 GeV region where they cluster when produced by Higgs boson decays. Here I am going to show the graph that is at the source of this idea, and the general conclusions that the theorists reach on the precision that ATLAS and CMS can obtain on that parameter.

First of all let me explain to outsiders what is the Higgs boson width. In order to do so I need to make a short digression.
It  happens in 1995, toward the end of Run 1B of the Fermilab Tevatron, in the middle of a otherwise anonymous store. The CDF detector is taking good data, and the shift crew in the control room take care of the usual business - a look at the colourful monitors that plaster the walls, a check at trigger rates, the logging of a few standard warnings issued by the data acquisition system, and the occasional browsing of e-mails.
"This time we're shooting through a brick!"

Larry Nodulman (during a discussion on the reconstruction of electrons in the CDF II detector, just refurbished with a new set of silicon microstrip layers (SVX'), more powerful and capable of identifying the impact parameter of charged tracks with a dozen micron accuracy, but also heavier and bulkier than its predecessor, and thus providing more material for multiple scattering of particles.)

An international team of high-energy physicists says the discovery of an electrically charged subatomic particle called Zc(4020) is a sign that they have begun to unveil a whole new family of four-quark objects.  

The Beijing Spectrometer (BESIII) collaboration previously announced the discovery of a four-quark particle called Zc(3900) in April of this year.  The results have come about through a dedicated study of the byproducts of the anomalous Y(4260) particle. 


These days I am trying to reconstruct some stories from my old experiment, CDF. The CDF experiment was conceived in 1979 and constructed in the early eighties at the Fermi laboratories in Batavia, near Chicago. CDF took the first proton-antiproton collisions in 1985, and it collected data in1987-88, 1992-96, and 2001-2011, thus becoming the longest-lasting particle physics experiment in the history of science.