What really is the Higgs bosonwhat is it made of dark matter and why are there three “families” of electrons. They may seem like niche, ultra-specialized questions, but in reality they have to do with something much more general: the answer to these three questions is, in fact, linked to the understanding of the deep mechanisms of nature that determine the fundamental properties of the universe. And help in finding these answers could one day come from the formidable combination of data that will be produced by the Future Circular Collider (FCC)the enormous particle accelerator being designed at CERN in Geneva, and the artificial intelligence who will be in charge of interpreting them. This is the vision of Mark Thomsonprofessor of Experimental Particle Physics at Cambridge and recently nominated by the British Government as a candidate for directorship of the CERN as successor to Fabiola Giannottiwhose second term will expire shortly. Thomson recently visited Italy and we caught up with him to get his take on the future of physics and the next challenges of CERN.
Neutrinos, so small and so important
Our conversation with Mark Thomson could only begin with neutrinosthe subject of his research for several decades. One of the most impenetrable secrets of the Universe seems to be preserved in neutrinos, specifically the so-called asymmetry between matter and antimatter. It is Thomson himself, co-leader of DUNE (Deep Underground Neutrino Experiment), one of the largest neutrino experiments in the world, who explains: “Neutrinos are clearly different from other particles. For a long time we thought they had zero mass, but now we know that They have almost zero mass, but not really zerobut a very very small mass, much smaller than all the other particles. So it’s clear that there’s something different about neutrinos, and at the moment we don’t know what makes them so special. But there is more,” he adds, “for the moment We still don’t understand why, after the Big Bang, there was matter left in the Universe. In fact, the Big Bang created particles and antiparticles, which should have annihilated each other, leaving only energy. On the other hand, it is evident that this did not happen: what happened was that for every billion antiparticles there were one billion and one particles. The question is therefore: How did this small asymmetry arise? Now, neutrinos may be the key. It is probably the best theory we have to explain how this asymmetry was generated. Two things are needed: the neutrinos must be the so-called Majorana fermionsthat is, they must coincide with their own antiparticle, but there must also be a violation of the symmetry between matter and antimatter for neutrinos. This is a very important question. We have not yet observed this violation, and One of the main objectives of the Dune project is precisely to demonstrate that neutrinos behave differently than antineutrinos.. Demonstrating that they violate this principle according to which matter and antimatter must behave in the same way would be a very important step in understanding why matter remains in the Universe.
Understanding whether or not the neutrino is a Majorana fermion, that is, whether or not it coincides with its antiparticle, is therefore of crucial importance for modern physics: and that is why We asked Thomson to take a chance on what his intuition suggests might be the right answer.. He did not hesitate: “Personally, I am convinced that The neutrino is a Majorana fermion.. The explanation is very elegant and, above all, it does not violate one of the fundamental laws of the Universe, namely Einstein’s special relativity. If I had to bet, I would do it on this possibility.”
And not just neutrinos
The physics of neutrinos, in short, is of capital importance. But it is not the only fundamental question still unresolved. Thomson identifies three others that are equally important. ‘The first refers to the Higgs bosonwhich we discovered in 2012: it is a completely different particle from any other we have seen before, and it gives mass to all the others. In a sense, therefore, it is everywhere: even in deep space, where there is nothing, the Higgs field exists. Because? What type of particle is it? Is it really an elementary particle?” Then, of course, there are the dark matter and the dark energy: “We know that everything we see is made of matter, and that’s just 5% of the Universe. There is at least another 25% made up of dark matter particles: we have some ideas about what they might be, and we know they must exist because we see its effects in galaxies, but we don’t go much further. Understanding what dark matter is is really crucial. Solving this question would immediately be worth a Nobel Prize. Finally, a problem related to it. electrons and some of their relatives: “The third question is a little more subtle. There are heavy versions of electrons, called muonsand even heavier versions, called tau leptons. And we don’t know why there are different types of electrons (we call them ‘families’ or ‘generations’) or why they have different masses. I think the origin of these families, why we have multiple copies of each particle, what determines their masses, and why they are so different is a huge question. Sometimes we call it the ‘flavor enigma’ and at the moment we know very little about it“.
The future circular collider: towards a new physics
To try to answer these (and other) questions (at least that’s what physicists hope) there will be the Future Circular Collider (FCC), a huge particle accelerator that is being planned at CERN in Geneva, and which should be the successor to the LHC, the instrument that made it possible to discover the Higgs boson. And he still has a lot to say: “Lhc still has a very exciting future ahead of it,” says Thomson, “the first priority is to complete its upgrades, making it more powerful: we hope to obtain more precise measurements and perhaps some new discoveries.” The perspectives of the Fcc are broader and more distant in time: We hope to have it up and running in 2045. and, for that to be possible, we have to start planning it now.” The scientific motivation for the first phase of Fcc is related to the Higgs boson: we will collide electrons and antielectrons to better understand the properties of the boson. We want to have our provision one machine giant, a huge microscope, that allows us to reach energies ten times higher than those of the LHC: there are so many things that we still do not understand in particle physics, and one of the most powerful tools to explore the unknown is basically make protons collide in the most energetic way possible. In exploring the unknown, tools, people and skills will be crucial. But artificial intelligence also will help tremendously“.
Article originally published in WIRED Italy. Adapted by Mauricio Serfatty Godoy.
#Mark #Thomson #candidate #director #CERN #Future #Circular #Collider #artificial #intelligence #future #physics
