Before, I went to my brother and I said to him: “They’ve catched the Higgs Boson!”
"What’s the Higgs boson?" He said.
I’ll try to explain…
The Standard Model is the theoretical model that describes everything that’s observed in the world of particle physics. We know there are twelve particles and four forces, and the Standard Model is our best understanding of how these particles and three of the forces are related. It was developed in the 70s, an nevertheless its effectiveness in describing and predicting a wide variety of phenomena, one of its essential components, a particle called Higgs boson, was, yet to be found in an experiment.
For more than three decades physicist have hunted for the Higgs boson. It wasn’t just for an obsession to have everything in its place: without the Higgs physicists could not explain how particles aquired mass.
In fact, the Higgs is responsible for the structure of the universe as we know it. It’s the Higgs that makes physical reality the way it is, with atoms, chemical reactions and life. No Higgs, no molecules. No planets. No people.
Strictly speaking, it’s better to say that without the Higgs, something even more exotic would have to do its job. That job, in physics speak, is “electroweak symmetry breaking.” In the universe’s earliest picoseconds, electromagnetism was a component of a more primordial “electroweak” force, incorporating what’s now called the weak force (known for its role in radioactivity). Equations describing the electroweak force are symmetric — that is, they describe electromagnetism and the weak force as equals. But somehow, the weak force split from electromagnetism. In other words, this mathematical symmetry between electro- and weak forces was “broken.”
Symmetry in nature’s laws is not optional; it ensures that the laws work the same for everybody, no matter where they are or how they move. But real life can get messy if something disrupts the symmetry. That’s what the Higgs does: It puts the universe on course to create reality’s complexities. (Nature’s Secrets Foretold by Tom Siegried)
If you don’t get it (I’m sure I don’t), try to watch this and this and read this and this, but trust me, the slipperest particle of physics is really important.
Today at CERN it was announced that a new particles was discovered, and that this particle is probably the Higgs.
The Higgs is very hard to detect because it doesn’t live long, it’s very fast in decaying in a burst of energy and other particles, so physicists need to smash other particles at incredibly high energies using some of the most complex machines ever built and look at the collisions. The collisions give you some tiny clues, but you need a lot of collisions to be sure.
How confident physicist are of today’s discovery? They see a strong signal between 125 and 126 GeV at about the 5 sigma level, that means “they can claim a 99.9999% confidence this signal is real!”
Sure, right now physicists are saying: “It’s a particle, it’s definetely a particle, but we don’t know for certain if it’s the Higgs.” Yet, it really looks like the Higgs. Someone says it’s a bit light, but the general feeling you get from the reactions to this discovery is that something huge is happened.
Brian Cox says it’s “without any doubt one of the biggest scientific discoveries of all time" and Themis Bowcock tells it’s a "giant leap for humankind" and Rolf Heuer says that: "We have reached a milestone in our understanding of nature”.
And now what? “We’re on the frontier now, we’re on the edge of a new exploration.”
“There’s so much other stuff we really don’t understand at all, and in that respect, the LHC is just at the beginning of trying to understand what we don’t know in the universe”
Let me tell you a story to explain what I mean. The story is an old story about my latest, greatest passion outside theoretical physics: an ancient scientist, or so I would say, even if often he is called a philosopher: Anaximander. I am fascinated by this character, Anaximander. I went into understanding what he did, and to me he’s a scientist. He did something that is very typical of science, and which shows some aspect of what science is. So what is the story with Anaximander? It’s the following, in brief: Until him, all the civilizations of the planet, everybody around the world, thought that the structure of the world was: the sky over our heads and the earth under our feet. There’s an up and a down, heavy things fall from the up to the down, and that’s reality. Reality is oriented up and down, heaven’s up and earth is down. Then comes Anaximander and says: no, is something else. ‘The earth is a finite body that floats in space, without falling, and the sky is not just over our head; it is all around.’ How he gets it? Well obviously he looks at the sky, you see things going around, the stars, the heavens, the moon, the planets, everything moves around and keeps turning around us. It’s sort of reasonable to think that below us is nothing, so it seems simple to get to this conclusion. Except that nobody else got to this conclusion. In centuries and centuries of ancient civilizations, nobody got there. The Chinese didn’t get there until the 17th century, when Matteo Ricci and the Jesuits went to China and told them. In spite of centuries of Imperial Astronomical Institute which was studying the sky. The Indians only learned this when the Greeks arrived to tell them. The Africans, in America, in Australia… nobody else got to this simple realization that the sky is not just over our head, it’s also under our feet. Why? Because obviously it’s easy to suggest that the earth sort of floats in nothing, but then you have to answer the question: why doesn’t it fall? The genius of Anaximander was to answer this question. We know his answer, from Aristotle, from other people. He doesn’t answer this question, in fact. He questions this question. He says why should it fall? Things fall toward the earth. Why the earth itself should fall? In other words, he realizes that the obvious generalization from every small heavy object falling, to the earth itself falling, might be wrong. He proposes an alternative, which is that objects fall towards the earth, which means that the direction of falling changes around the earth. This means that up and down become notions relative to the earth. Which is rather simple to figure out for us now: we’ve learned this idea. But if you think of the difficulty when we were children, to understand how people in Sydney could live upside-down, clearly requires some changing in something structural in our basic language in terms of which we understand the world. In other words, up and down means something different before and after Anaximander’s revolution. He understands something about reality, essentially by changing something in the conceptual structure that we have in grasping reality. In doing so, he is not doing a theory; he understands something which in some precise sense is forever. It’s some uncovered truth, which to a large extent is a negative truth. He frees ourselves from prejudice, a prejudice that was ingrained in the conceptual structure we had for thinking about space.
Theoretical physicist Carlo Rovelli explains why science Is not about certainty, instead:
Science is about finding the most reliable way of thinking, at the present level of knowledge. Science is extremely reliable; it’s not certain. In fact, not only it’s not certain, but it’s the lack of certainty that grounds it. Scientific ideas are credible not because they are sure, but because they are the ones that have survived all the possible past critiques, and they are the most credible because they were put on the table for everybody’s criticism.
Possibly the best piece about philosophy of science that I’ve read on internet so far.
New data from Tevatron experiments “strongly point toward the existence of the Higgs boson”. There’s confidence, but the results are not conclusive.
: Can you please do a brief explanation of quarks? I looked it up but wrapping my head around it is a bit difficult.
Quarks and leptons are the building blocks of matter, they are the “elementary particles”, that means that it is thought they can’t be broken down into other smaller particles. Quarks in particular combine forming composite particles collectively called hadrons. Protons and neutrons are hadrons. There are 6 types (flavors) of quarks: up, down, charm, strange, top, bottom. The quark model was indipendently proposed by Murray Gell-Mann and George Zweiz in 1964. While Zweig preferred the name ace for these particles, the name quark, proposed by Gell-Mann who took it from the book “Finnegan’s Wake” by James Joyce, became the popular (and official) one.
If you want to know something more check this out: Quarks.
The Sudbury Neutrino Observatory is a neutrino observatory located about 2 km underground in Vale Inco's Creighton Mine in Sudbury, Canada. It was designed to detect solar neutrinos using a 12 meter diameter acrylic vessel filled with 1000 tonnes of heavy water. Neutrinos reacts with the heavy water (D2O) producing flashes of light called Cherenkov radiation. This light is then detected by an array of 9600 photomultiplier tubes mounted on a structure surrounding the vessel.
Pictures via Interactions.org (#1, #2)
Front view of the semiconductor trackers for ATLAS, one of the four enormous detectors for the Large Hadron Collider at CERN (via Fermilab)
Super-Kamiokande Neutrino Detection Experiment is a neutrino observatory under Mount Kamioka, in Japan. Its purpose is to investigate the neutrino properties observing solar neutrinos, atmospheric neutrinos and man-made neutrinos.
The Super-Kamiokande detector consists of a stainless-stell tank that can contain 5 0,000 ton of pure water. On the tank wall there are about 13000 20 inch PMTs (Photo-Multiplier Tubes).
Borexino is an international experiment, located deep underground in the Gran Sasso National Laboratory of Italy. Its main goal is the study of the properties of a subatomic elementary particle, called the neutrino. The experiment is designed for the observation of low-energy (sub-MeV) solar neutrinos, with the specific goal of measuring the Be-7 neutrino flux from the Sun.
In the pictures above: a view of the internal of the Borexino Stainless Steel Sfere and the inside view of Borexino detector filled with water.