The ‘particle of God’ explained to mortals

The ‘particle of God’ explained to mortals

January 14, 2018 0 By Michael

The European Laboratory for Particle Physics ( CERN ) in Geneva has once again launched the Large Hadron Collider (LHC), with which a couple of years ago, one of the most important discoveries in the field of particle physics in recent decades: the Higgs boson. We explain what is called the ‘particle of God’ and why its detection was so important.

The ‘particle of God’ was first manifested among men on July 4, 2012. Better known as Higgs Boson, a group of physicists proposed its existence in 1964 but was not confirmed until the spring of 2013 at CERN.

Scientists at the LHC, a CERN particle accelerator, proclaimed their discovery after more than half a century of searching and the discovery shocked the world. However, beyond scientific circles, many uninitiated ignore what is this boson and why its existence is relevant.

So, what is the Higgs boson?

In essence and in a crude way, it is an elementary particle that explains the difference between the masses of the different particles that make up nature. To be able to delve into this phenomenon and come to understand it, it is necessary to previously refresh a series of concepts.

First, matter is composed of atoms. These atoms, in turn, are formed by a central nucleus, with neutrons and protons, and around them electrons revolve.

However, these protons and neutrons are composed of even smaller particles, called quarks . They are elementary particles, just like electrons, which are indivisible.

What is the problem?

In the 1960s, scientists tried to understand how protons and neutrons worked inside, and the theories did not quite fit.

The physicists did not understand what the enormous mass differences between the different elementary particles were due to. For example, the ‘top’ quark (one of the six types that exist) is much heavier than an electron. Concretely, its mass is 350,000 times greater. This is the same weight difference between a sardine and a whale.

The questions were open and very deep: What gives the mass to the particles? What is mass really? Why do these differences exist?

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Image of a section of the tunnel of the Large Hadron Collider (CERN)

To answer all these questions, in 1964 the British physicist Peter Higgs proposed, together with other colleagues, a solution. They presented a theory that ensured that all space is filled with a field that interacts with elementary particles and this is what gives them mass.

It is the ‘Higgs field’, which permeates the entire universe.

Like fish in the water

To better understand its operation, it is possible to establish a simple analogy. The elementary particles are immersed in the Higgs field like the fish in the water. A sardine in the sea, being small, interacts very little with the environment and can move quickly. On the contrary, a whale, with a much larger size, interacts with more water and will move more slowly.

When transferred to the subatomic case, the idea is that the greater the interaction of a particle with the Higgs field, the greater its mass. One could say that this field “slows down” more the heavier particles, just as it happens with water and fish.

Thus, an electron interacts little with the Higgs field, so it moves easily through it. In other words, the Higgs field makes the electron have a minimum mass (would be the case of the sardine).

On the other hand, the ‘top’ quark has a very strong interaction with the Higgs field, so it moves slowly. Or what is the same, it is very heavy (like the whale).

According to this theory, the mass would not be an intrinsic property of the particles but the result of an interaction with the Higgs field.

Where does the Higgs boson appear?

In the same way that water is composed of H2O molecules, the Higgs field is made up of an uncountable number of Higgs bosons.

To prove that this theory proposed in 1964 was true, it was necessary to find these bosons. For this, the large particle accelerators were built.

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Higgs candidate event from proton collisions (CMR | CERN)

Why was it so complicated to observe it?

For two fundamental reasons. First of all, to generate a Higgs boson, very high energy intensities are needed, similar to those of the Big Bang . To reproduce these conditions, it was necessary to build large particle accelerators such as the CERN LHC, where it was finally detected.

Second, once the Higgs boson is generated, it disintegrates very quickly and disappears before it can be observed. In fact, what is detected in the experiments is not the Higgs boson, but the residues it leaves when it decomposes.

What did physicists do at the LHC?

In a very simplified way, in this accelerator proton beams were collided head-on at very high speeds to generate high-energy instants and observe which particles appeared. For fractions of a second, the LHC managed to reproduce the Big Bang conditions and new subatomic particles were formed, including the Higgs boson.

Until recently, accelerators were not able to reproduce these conditions and thus get the protons colliding at high enough speeds to produce the Higgs boson. For that reason, it could not be definitively detected until a couple of years ago.

Where does the term ‘particle of God’ come from?

The Nobel Prize for Physics Leon Lederman wrote in the nineties a book in which he referred to the Higgs boson as “the goddamn particle”, that is, “the damn particle”, because it was difficult to detect it.

In a display of originality, the text editor decided to replace the name with “the God particle”, that is, “the particle of God”. Since then, the Higgs boson has been renamed.

However, some researchers prefer the nickname of “the champagne bottle particle”. This term refers to the anecdote that relates that British Minister of Science William Waldegrave offered this gift to anyone who was able to explain what the Higgs boson was.

And now that?

The discovery of the Higgs boson was an event in the scientific community because it constitutes a victory of the Standard Model of Physics, that is, the theory that encompasses all knowledge about the subatomic world.

This model predicts what particles form matter and what forces interact between them. Likewise, it foresaw the existence of the Higgs boson and its confirmation supports the model and strengthens current ideas. If this finding had not occurred, the physicists would have had to assume that some of these approaches were erroneous and propose alternative formulations.

However, the Standard Model does not become a complete theory, since it does not include gravity, which is one of the four fundamental forces of nature. Nor does it explain what dark matter and energy are. Many scientists are convinced that the confirmation of the existence of the Higgs boson will allow advances in theories such as supersymmetry or the unification of the forces of nature.

From now on, investigations should continue in this line to unravel the secrets of nature.

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