Mathematics
Who gives the mass of the Higgs boson. About the Higgs boson in simple terms - what scientists discovered with the help of the hadron collider, what is this boson needed for? If there were no Higgs field

Who gives the mass of the Higgs boson. About the Higgs boson in simple terms - what scientists discovered with the help of the hadron collider, what is this boson needed for? If there were no Higgs field

- What will the new particle give to scientists and ordinary people?

The main directions of development of modern fundamental physics are physics elementary particles and cosmology - the science of the evolution of the Universe. In the last 10–15 years, it has become clear that the devices of the micro- and macroworld are closely connected with each other. A discovery in one area gives a strong impetus to the development of another.

The discovery of the Higgs boson will allow scientists to confirm that the basis modern physics- The Standard Model is a reliable basis for the further development of our ideas about Nature. The prediction of the existence of the Higgs particle was not confirmed experimentally for decades, which was a dark spot in all of particle physics. The discovery of the Higgs boson confirms the correctness of the main direction of development and greatly narrows the possibilities alternative theories both in the micro and macro world. This will allow for more efficient use of budget funds.

- Where is it possible to apply the discovery of a new boson?

It's too early to talk about this. First of all, you need to thoroughly study its properties and only then think about application. The possibilities of using Higgs particles to explain the earliest stage of the formation of the Universe are already being explored. And also the phenomenon of dark energy. The latter, as yet unexplained, phenomenon was discovered in 1998 while observing the accelerated retreat of quasars, the brightest objects in the Universe. This effect can be explained only by assuming that it is not entirely normal properties matter that fills the Universe.

- What impetus to the development of new technologies can this particle give?

It is known from the history of science that fundamental discoveries do not immediately lead to the emergence of new technologies. Fine famous example- Michael Faraday's discovery of the laws of electromagnetic induction, the application of which in technology seemed extremely doubtful. Now, almost 200 years later, it is difficult to imagine our world without electricity. Another example is the neutrino, discovered in 1933, which interacts so weakly with matter that it can pass through the Earth without even noticing it. For a long time it seemed that a particle with such a property would be difficult to find application for. However, now scientists are already trying to use neutrinos to transmit signals through dense media and detect traces of nuclear reactions at great distances.

The situation is similar with the Higgs particle. Apparently, more than a dozen years must pass before the possibilities of using this phenomenon in technology become obvious. First of all, related fields of science will develop, then the influence will spread further. It may turn out that only future generations will be able to benefit from the fruits of this discovery, just as we now benefit from Faraday’s discoveries.

Development modern science happening at an accelerated pace and in a variety of directions. Thus, the Russian heavy ion accelerator, Nika, is being built in Dubna. It will operate in the energy region that is not covered by any of the existing installations in the world, including the Large Hadron Collider. It is in this energy region that there is a chance to obtain a mixed phase of nuclear matter - a state in which particles released from the nucleus - quarks and gluons - simultaneously exist. So far, no one in the world has been able to “catch” free quarks.

Speaking in simple language, the Higgs boson is the most expensive particle of all time. If all it took was a vacuum tube and a couple of brilliant minds, for example, the search for the Higgs boson required the creation of experimental energy rarely seen on Earth. The Large Hadron Collider needs no introduction, being one of the most famous and successful scientific experiments, but its profile particle, as before, is shrouded in mystery for most of the population. It has been called the God Particle, but thanks to the efforts of literally thousands of scientists, we no longer have to take its existence for granted.

The last unknown

What is it and what is the importance of its discovery? Why has it become the subject of so much hype, funding and misinformation? For two reasons. First, it was the last undiscovered particle needed to confirm the Standard Model of physics. Its discovery meant that an entire generation scientific publications was not in vain. Secondly, this boson gives other particles their mass, which gives it special meaning and some “magic”. We tend to think of mass as an intrinsic property of things, but physicists think differently. In simple terms, the Higgs boson is a particle without which mass fundamentally does not exist.

One more field

The reason lies in the so-called Higgs field. It was described even before the Higgs boson, since physicists calculated it for the needs of their own theories and observations, which required the presence of a new field, the action of which would extend to the entire Universe. Reinforcing hypotheses by inventing new parts of the universe is dangerous. In the past, for example, this led to the creation of the theory of the ether. But the more mathematical calculations were made, the more physicists realized that the Higgs field must exist in reality. The only problem was the lack of practical possibilities for observing it.

In the Standard Model, physicists obtain mass through a mechanism based on the existence of the Higgs field that permeates all space. It creates Higgs bosons, which requires a large amount of energy, and this is main reason why scientists need modern particle accelerators to conduct high-energy experiments.

Where does mass come from?

The strength of weak nuclear interactions decreases rapidly with increasing distance. According to quantum field theory, this means that the particles that are involved in its creation - W and Z bosons - must have mass, unlike gluons and photons, which have no mass.

The problem is that gauge theories only deal with massless elements. If gauge bosons have mass, then such a hypothesis cannot be reasonably defined. The Higgs mechanism avoids this problem by introducing a new field called the Higgs field. At high energies, gauge bosons have no mass, and the hypothesis works as expected. At low energies, the field causes symmetry breaking, which allows elements to have mass.

What is the Higgs boson?

The Higgs field produces particles called Higgs bosons. The theory does not specify their mass, but as a result of the experiment it was determined that it is equal to 125 GeV. In simple terms, the existence of the Higgs boson finally confirmed the Standard Model.

The mechanism, field and boson are named after Scottish scientist Peter Higgs. Although he was not the first to propose these concepts, but, as often happens in physics, he simply turned out to be the one after whom they were named.

Symmetry breaking

It was believed that the Higgs field was responsible for the fact that particles that should not have mass did. This is a universal medium that gives massless particles different masses. This violation of symmetry is explained by analogy with light - all wavelengths move in a vacuum at the same speed, but in a prism each wavelength can be isolated. This is, of course, an incorrect analogy, since white light contains all wavelengths, but the example shows how the Higgs field appears to create mass due to symmetry breaking. The prism breaks the speed symmetry of different wavelengths of light by separating them, and the Higgs field is thought to break the mass symmetry of some particles that are otherwise symmetrically massless.

How to explain the Higgs boson in simple terms? Only recently have physicists realized that if the Higgs field really exists, its action would require the presence of a suitable carrier with properties that make it observable. It was assumed that this particle belonged to bosons. The Higgs boson in simple terms is the so-called carrier force, the same as photons, which are carriers electromagnetic field Universe. Photons, in a sense, are local excitations of it, just as the Higgs boson is a local excitation of its field. Proving the existence of a particle with the properties expected by physicists was actually equivalent to direct proof of the existence of a field.

Experiment

Many years of planning have allowed the Large Hadron Collider (LHC) to become an experiment sufficient to potentially disprove the Higgs boson theory. The 27 km ring of super-powerful electromagnets can accelerate charged particles to significant fractions, causing collisions of sufficient force to separate them into components, as well as deform the space around the point of impact. According to calculations, at a collision energy of a sufficiently high level, a boson can be charged so that it decays and this can be observed. This energy was so great that some even panicked and predicted the end of the world, and the imagination of others has gone so far that the discovery of the Higgs boson has been described as a glimpse into an alternate dimension.

Final confirmation

Initial observations seemed to actually refute the predictions, and no sign of the particle could be found. Some researchers involved in the campaign to spend billions of dollars even appeared on television and meekly stated the fact that the refutation scientific theory just as important as its confirmation. After some time, however, the measurements began to add up to the overall picture, and on March 14, 2013, CERN officially announced confirmation of the existence of the particle. There is evidence to suggest the existence of multiple bosons, but this idea needs further study.

Two years after CERN announced the discovery of the particle, scientists working at the Large Hadron Collider were able to confirm it. On the one hand, it became a huge victory science, and on the other hand, many scientists were disappointed. If anyone was hoping that the Higgs boson would be the particle that would lead to weird and wonderful regions beyond the Standard Model - supersymmetry, dark matter, dark energy - then, unfortunately, this turned out not to be the case.

A study published in Nature Physics confirmed the decay into fermions. predicts that, in simple terms, the Higgs boson is the particle that gives fermions their mass. The collider's CMS detector finally confirmed their decay into fermions - down quarks and tau leptons.

Higgs boson in simple terms: what is it?

This study definitively confirmed that this is the Higgs boson predicted by the Standard Model of particle physics. It is located in the mass-energy region of 125 GeV, has no spin, and can decay into many lighter elements - pairs of photons, fermions, etc. Thanks to this, we can confidently say that the Higgs boson, in simple terms, is a particle , giving mass to everything.

The standard behavior of the newly discovered element was disappointing. If its decay were even slightly different, it would be related to fermions differently, and new lines of research would emerge. On the other hand, this means that we have not advanced one step beyond the Standard Model, which does not take into account gravity, dark energy, dark matter and other bizarre phenomena of reality.

Now we can only guess what caused them. The most popular theory is supersymmetry, which states that every Standard Model particle has an incredibly heavy superpartner (thus making up 23% of the Universe - dark matter). Upgrading the collider to double its collision energy to 13 TeV will likely enable detection of these superparticles. Otherwise, supersymmetry will have to wait for the construction of a more powerful successor to the LHC.

Future prospects

So what will physics be like after the Higgs boson? The LHC just recently reopened with major improvements and is capable of seeing everything from antimatter to dark energy. It is believed to interact with the normal one solely through gravity and through the creation of mass, and the significance of the Higgs boson is key to understanding exactly how this happens. The main flaw of the Standard Model is that it cannot explain the force of gravity - such a model could be called the Grand Unified Theory - and some believe that the particle and the Higgs field may provide the bridge that physicists are so desperate to find.

The existence of the Higgs boson has been confirmed, but its complete understanding is still very far away. Will future experiments refute supersymmetry and the idea of its decomposition into dark matter itself? Or will they confirm every last detail of the standard model's predictions about the properties of the Higgs boson, and this area of research will be finished forever?

We, the Quantuz team, (trying to join the GT community) offer our translation of the section of the particleadventure.org website dedicated to the Higgs boson. In this text we have excluded uninformative pictures ( full version see original). The material will be of interest to anyone interested in the latest achievements of applied physics.

The role of the Higgs boson

The Higgs boson was the last particle discovered in the Standard Model. This is a critical component of the theory. His discovery helped confirm the mechanism of how fundamental particles acquire mass. These fundamental particles in the Standard Model are quarks, leptons, and force-carrying particles.

1964 theory

In 1964, six theoretical physicists hypothesized the existence of a new field (like an electromagnetic field) that fills all space and solves a critical problem in our understanding of the universe.

Independently, other physicists developed a theory of fundamental particles, eventually called the Standard Model, which provided phenomenal accuracy (the experimental accuracy of some parts of the Standard Model reaches 1 in 10 billion. This is equivalent to predicting the distance between New York and San Francisco with an accuracy of about 0.4 mm). These efforts turned out to be closely interconnected. The Standard Model needed a mechanism for particles to acquire mass. Field theory was developed by Peter Higgs, Robert Brout, Francois Englert, Gerald Guralnick, Carl Hagen and Thomas Kibble.

boson

Peter Higgs realized that, by analogy with other quantum fields, there must be a particle associated with this new field. It must have a spin equal to zero and, thus, be a boson - a particle with an integer spin (unlike fermions, which have a half-integer spin: 1/2, 3/2, etc.). And indeed it soon became known as the Higgs Boson. Its only drawback was that no one saw it.

What is the mass of the boson?

Unfortunately, the theory that predicted the boson did not specify its mass. Years passed until it became clear that the Higgs boson must be extremely heavy and most likely beyond the reach of facilities built before the Large Hadron Collider (LHC).

Remember that according to E=mc 2, the greater the mass of the particle, the more energy is needed to create it.

At the time the LHC began collecting data in 2010, experiments at other accelerators showed that the mass of the Higgs boson should be greater than 115 GeV/c2. During experiments at the LHC it was planned to look for evidence of a boson in the mass range 115-600 GeV/c2 or even higher than 1000 GeV/c2.

Every year, it was experimentally possible to exclude bosons with higher masses. In 1990 it was known that the required mass should be greater than 25 GeV/c2, and in 2003 it turned out that it was greater than 115 GeV/c2

Collisions at the Large Hadron Collider could produce a lot of interesting things

Dennis Overbye in the New York Times talks about recreating the conditions of a trillionth of a second after Big Bang and says:

« ...the remains of [the explosion] in this part of the cosmos have not been seen since the Universe cooled 14 billion years ago - the spring of life is fleeting, over and over again in all its possible variations, as if the Universe were participating in its own version of the movie Groundhog Day»

One of these “remains” may be the Higgs boson. Its mass must be very large, and it must decay in less than a nanosecond.

Announcement

After half a century of anticipation, the drama became intense. Physicists slept outside the auditorium to take their seats at a seminar at the CERN laboratory in Geneva.

Ten thousand miles away, on the other side of the planet, at a prestigious international conference on particle physics in Melbourne, hundreds of scientists from all corners of the globe gathered to hear the seminar broadcast from Geneva.

But first, let's take a look at the background.

Fireworks 4th of July

On July 4th, 2012, the directors of the ATLAS and CMS experiments at the Large Hadron Collider presented their latest results in the search for the Higgs boson. There were rumors that they were going to report more than just a results report, but what?

Sure enough, when the results were presented, both collaborations that carried out the experiments reported that they had found evidence for the existence of a “Higgs boson-like” particle with a mass of about 125 GeV. It was definitely a particle, and if it is not the Higgs boson, then it is a very high-quality imitation of it.

The evidence was not inconclusive; the scientists had five-sigma results, meaning there was less than a one in a million chance that the data was simply a statistical error.

The Higgs boson decays into other particles

The Higgs boson decays into other particles almost immediately after it is produced, so we can only observe its decay products. The most common decays (among those that we can see) are shown in the figure:

Each decay mode of the Higgs boson is known as a "decay channel" or "decay mode". Although the bb mode is common, many other processes produce similar particles, so if you observe bb decay, it is very difficult to tell whether the particles are due to the Higgs boson or something else. We say that the bb decay mode has a “broad background”.

The best decay channels for searching for the Higgs boson are the channels of two photons and two Z bosons.*

*(Technically, for a 125 GeV Higgs boson mass, decay into two Z bosons is not possible, since the Z boson has a mass of 91 GeV, causing the pair to have a mass of 182 GeV, greater than 125 GeV. However, what we observe is a decay into a Z-boson and a virtual Z-boson (Z*), whose mass is much smaller.)

Decay of the Higgs boson to Z + Z

Z bosons also have several decay modes, including Z → e+ + e- and Z → µ+ + µ-.

The Z + Z decay mode was quite simple for the ATLAS and CMS experiments, with both Z bosons decaying in one of two modes (Z → e+ e- or Z → µ+ µ-). The figure shows four observed decay modes of the Higgs boson:

The end result is that sometimes the observer will see (in addition to some unbound particles) four muons, or four electrons, or two muons and two electrons.

What the Higgs boson would look like in the ATLAS detector

In this event, the “jet” (jet) appeared going down, and the Higgs boson was going up, but it decayed almost instantly. Each collision picture is called an "event".

Example of an event with a possible decay of the Higgs boson in the form of a beautiful animation of the collision of two protons in the Large Hadron Collider, you can see it on the source website at this link.

In this event, a Higgs boson can be produced and then immediately decays into two Z bosons, which in turn immediately decay (leaving two muons and two electrons).

Mechanism that gives mass to particles

The discovery of the Higgs boson is an incredible clue to how fundamental particles acquire mass, as claimed by Higgs, Brout, Engler, Gerald, Karl and Kibble. What kind of mechanism is this? It's very complicated mathematical theory, but her main idea can be understood by a simple analogy.

Imagine a space filled with the Higgs field, like a party of physicists calmly communicating with each other with cocktails...
At one point, Peter Higgs enters and creates excitement as he moves across the room, attracting a group of fans with every step...

Before entering the room, Professor Higgs could move freely. But after entering the room full of physicists his speed decreased. A group of fans slowed his movement across the room; in other words, he gained mass. This is analogous to a massless particle acquiring mass when interacting with the Higgs field.

But all he wanted was to get to the bar!

(The idea for the analogy belongs to Prof. David J. Miller from University College London, who won the prize for an accessible explanation of the Higgs boson - © CERN)

How does the Higgs boson get its own mass?

On the other hand, as the news spreads around the room, they also form groups of people, but this time exclusively of physicists. Such a group can slowly move around the room. Like other particles, the Higgs boson gains mass simply by interacting with the Higgs field.

Finding the mass of the Higgs boson

How do you find the mass of the Higgs boson if it decays into other particles before we detect it?

If you decide to assemble a bicycle and want to know its mass, you should add up the masses of the bicycle parts: two wheels, frame, handlebars, saddle, etc.

But if you want to calculate the mass of the Higgs boson from the particles it decayed into, you can't simply add up the masses. Why not?

Adding the masses of Higgs boson decay particles does not work, since these particles have enormous kinetic energy compared to the rest energy (remember that for a particle at rest E = mc 2). This occurs due to the fact that the mass of the Higgs boson is much greater than the masses of the final products of its decay, so the remaining energy goes somewhere, namely, into the kinetic energy of the particles that arise after the decay. Relativity tells us to use the equation below to calculate the "invariant mass" of a set of particles after decay, which will give us the mass of the "parent", the Higgs boson:

E 2 =p 2 c 2 +m 2 c 4

Finding the mass of the Higgs boson from its decay products

Quantuz note: here we are a little unsure of the translation, since there are special terms involved. We suggest comparing the translation with the source just in case.

When we talk about decay like H → Z + Z* → e+ + e- + µ+ + µ-, then the four possible combinations shown above could arise from both Higgs boson decay and background processes, so we need to look at the histogram of the total mass of the four particles in these combinations.

The mass histogram implies that we are observing a huge number of events and noting the number of those events when the resulting invariant mass is obtained. It looks like a histogram because the invariant mass values are divided into columns. The height of each column shows the number of events in which the invariant mass is in the corresponding range.

We might imagine that these are the results of the decay of the Higgs boson, but this is not the case.

Higgs boson data from background

The red and purple areas of the histogram show the "background" in which the number of four-lepton events expected to occur without the participation of the Higgs boson.

The blue area (see animation) represents the "signal" prediction, in which the number of four-lepton events suggests the result of the decay of the Higgs boson. The signal is placed at the top of the background because in order to get the total predicted number of events, you simply add up all the possible outcomes of events that could occur.

The black dots show the number of observed events, while the black lines passing through the dots represent the statistical uncertainty in these numbers. The rise in data (see next slide) at 125 GeV is a sign of a new 125 GeV particle (Higgs boson).

An animation of the evolution of data for the Higgs boson as it accumulates is on the original website.

The Higgs boson signal rises slowly above the background.

Data from the Higgs boson decaying into two photons

Decay into two photons (H → γ + γ) has an even wider background, but nevertheless the signal is clearly distinguished.

This is a histogram of the invariant mass for the decay of the Higgs boson into two photons. As you can see, the background is very wide compared to the previous chart. This is because there are many more processes that produce two photons than there are processes that produce four leptons.

The dashed red line shows the background and the thick red line shows the sum of the background and the signal. We see that the data are in good agreement with a new particle around 125 GeV.

Disadvantages of early data

The data were compelling but not perfect and had significant limitations. By July 4, 2012, there were not enough statistics to determine the rate at which a particle (the Higgs boson) decays into the various sets of less massive particles (the so-called "branching proportions") predicted by the Standard Model.

The "branching ratio" is simply the probability that a particle will decay through a given decay channel. These proportions are predicted by the Standard Model and measured by repeatedly observing the decays of the same particles.

The following graph shows the best measurements of branching proportions we can make as of 2013. Since these are the proportions predicted by the Standard Model, the expectation is 1.0. The points are the current measurements. Obviously, the error bars (red lines) are mostly still too large to draw serious conclusions. These segments are shortened as new data is received and the points may possibly move.

How do you know that a person is observing a candidate event for the Higgs boson? There are unique parameters that distinguish such events.

Is the particle a Higgs boson?

While the new particle had been detected to decay, the rate at which it was happening was still unclear by July 4th. It was not even known whether open particle the correct quantum numbers - that is, whether it has the spin and parity required for the Higgs boson.

In other words, on the 4th of July the particle looked like a duck, but we needed to make sure it swam like a duck and quacked like a duck.

All results from the ATLAS and CMS experiments of the Large Hadron Collider (as well as the Tevatron collider at Fermilab) after July 4, 2012 showed remarkable agreement with the expected branching proportions for the five decay modes discussed above, and agreement with the expected spin (equal to zero) and parity (equal to +1), which are the fundamental quantum numbers.

These parameters are important in determining whether the new particle is truly the Higgs boson or some other unexpected particle. So all available evidence points to the Higgs boson from the Standard Model.

Some physicists considered this a disappointment! If the new particle is the Higgs boson from the Standard Model, then the Standard Model is essentially complete. All that can now be done is to take measurements with increasing precision of what has already been discovered.

But if the new particle turns out to be something not predicted by the Standard Model, it will open the door to many new theories and ideas to be tested. Unexpected results always require new explanations and help push theoretical physics forward.

Where did mass come from in the Universe?

In ordinary matter, the bulk of the mass is contained in atoms, and, to be more precise, is contained in a nucleus consisting of protons and neutrons.

Protons and neutrons are made of three quarks, which gain their mass by interacting with the Higgs field.

BUT... the quark masses contribute about 10 MeV, which is about 1% of the mass of the proton and neutron. So where does the remaining mass come from?

It turns out that the proton mass arises due to kinetic energy its constituent quarks. As you, of course, know, mass and energy are related by the equality E=mc 2.

So only a small fraction of the mass of ordinary matter in the Universe belongs to the Higgs mechanism. However, as we will see in the next section, the Universe would be completely uninhabitable without the Higgs mass, and there would be no one to discover the Higgs mechanism!

If there were no Higgs field?

If there was no Higgs field, what would the Universe be like?

It's not that obvious.

Certainly nothing would bind the electrons in the atoms. They would fly apart at the speed of light.

But quarks are bound by a strong interaction and cannot exist in a free form. Some bound states of quarks might be preserved, but it is not clear about protons and neutrons.

All of this would probably be nuclear-like matter. And maybe all this collapsed as a result of gravity.

A fact of which we are certain: the Universe would be cold, dark and lifeless.
So the Higgs boson saves us from a cold, dark, lifeless universe where there are no people to discover the Higgs boson.

Is the Higgs boson a boson from the Standard Model?

We know for sure that the particle we discovered is the Higgs boson. We also know that it is very similar to the Higgs boson from the Standard Model. But there are two points that are still not proven:

1. Despite the fact that the Higgs boson is from the Standard Model, there are small discrepancies indicating the existence new physics(now unknown).
2. There are more than one Higgs bosons, with different masses. This also suggests that there will be new theories to explore.

Only time and new data will reveal either the purity of the Standard Model and its boson or exciting new physical theories.

We, the Quantuz team, (trying to join the GT community) offer our translation of the section of the particleadventure.org website dedicated to the Higgs boson. In this text we have excluded uninformative pictures (for the full version, see the original). The material will be of interest to anyone interested in the latest achievements of applied physics.

The role of the Higgs boson

1964 theory

In 1964, six theoretical physicists hypothesized the existence of a new field (like an electromagnetic field) that fills all space and solves a critical problem in our understanding of the universe.

boson

What is the mass of the boson?

Remember that according to E=mc 2, the greater the mass of the particle, the more energy is needed to create it.

Collisions at the Large Hadron Collider could produce a lot of interesting things

Dennis Overbye in the New York Times talks about recreating the conditions of a trillionth of a second after the Big Bang and says:

One of these “remains” may be the Higgs boson. Its mass must be very large, and it must decay in less than a nanosecond.

Announcement

After half a century of anticipation, the drama became intense. Physicists slept outside the auditorium to take their seats at a seminar at the CERN laboratory in Geneva.

But first, let's take a look at the background.

Fireworks 4th of July

The evidence was not inconclusive; the scientists had five-sigma results, meaning there was less than a one in a million chance that the data was simply a statistical error.

The Higgs boson decays into other particles

The best decay channels for searching for the Higgs boson are the channels of two photons and two Z bosons.*

Decay of the Higgs boson to Z + Z

Z bosons also have several decay modes, including Z → e+ + e- and Z → µ+ + µ-.

The end result is that sometimes the observer will see (in addition to some unbound particles) four muons, or four electrons, or two muons and two electrons.

What the Higgs boson would look like in the ATLAS detector

In this event, the “jet” (jet) appeared going down, and the Higgs boson was going up, but it decayed almost instantly. Each collision picture is called an "event".

In this event, a Higgs boson can be produced and then immediately decays into two Z bosons, which in turn immediately decay (leaving two muons and two electrons).

Mechanism that gives mass to particles

The discovery of the Higgs boson is an incredible clue to how fundamental particles acquire mass, as claimed by Higgs, Brout, Engler, Gerald, Karl and Kibble. What kind of mechanism is this? This is a very complex mathematical theory, but its main idea can be understood by a simple analogy.

Before entering the room, Professor Higgs could move freely. But after entering a room full of physicists, his speed decreased. A group of fans slowed his movement across the room; in other words, he gained mass. This is analogous to a massless particle acquiring mass when interacting with the Higgs field.

But all he wanted was to get to the bar!

(The idea for the analogy belongs to Prof. David J. Miller from University College London, who won the prize for an accessible explanation of the Higgs boson - © CERN)

How does the Higgs boson get its own mass?

Finding the mass of the Higgs boson

How do you find the mass of the Higgs boson if it decays into other particles before we detect it?

If you decide to assemble a bicycle and want to know its mass, you should add up the masses of the bicycle parts: two wheels, frame, handlebars, saddle, etc.

But if you want to calculate the mass of the Higgs boson from the particles it decayed into, you can't simply add up the masses. Why not?

E 2 =p 2 c 2 +m 2 c 4

Finding the mass of the Higgs boson from its decay products

Quantuz note: here we are a little unsure of the translation, since there are special terms involved. We suggest comparing the translation with the source just in case.

We might imagine that these are the results of the decay of the Higgs boson, but this is not the case.

Higgs boson data from background

The red and purple areas of the histogram show the "background" in which the number of four-lepton events expected to occur without the participation of the Higgs boson.

An animation of the evolution of data for the Higgs boson as it accumulates is on the original website.

The Higgs boson signal rises slowly above the background.

Data from the Higgs boson decaying into two photons

Decay into two photons (H → γ + γ) has an even wider background, but nevertheless the signal is clearly distinguished.

The dashed red line shows the background and the thick red line shows the sum of the background and the signal. We see that the data are in good agreement with a new particle around 125 GeV.

Disadvantages of early data

How do you know that a person is observing a candidate event for the Higgs boson? There are unique parameters that distinguish such events.

Is the particle a Higgs boson?

While the new particle had been detected to decay, the rate at which it was happening was still unclear by July 4th. It was not even known whether the discovered particle had the correct quantum numbers—that is, whether it had the spin and parity required for the Higgs boson.

In other words, on the 4th of July the particle looked like a duck, but we needed to make sure it swam like a duck and quacked like a duck.

Where did mass come from in the Universe?

In ordinary matter, the bulk of the mass is contained in atoms, and, to be more precise, is contained in a nucleus consisting of protons and neutrons.

Protons and neutrons are made of three quarks, which gain their mass by interacting with the Higgs field.

BUT... the quark masses contribute about 10 MeV, which is about 1% of the mass of the proton and neutron. So where does the remaining mass come from?

It turns out that the mass of a proton arises from the kinetic energy of its constituent quarks. As you, of course, know, mass and energy are related by the equality E=mc 2.

If there were no Higgs field?

If there was no Higgs field, what would the Universe be like?

It's not that obvious.

Certainly nothing would bind the electrons in the atoms. They would fly apart at the speed of light.

But quarks are bound by a strong interaction and cannot exist in a free form. Some bound states of quarks might be preserved, but it is not clear about protons and neutrons.

All of this would probably be nuclear-like matter. And maybe all this collapsed as a result of gravity.

A fact of which we are certain: the Universe would be cold, dark and lifeless.
So the Higgs boson saves us from a cold, dark, lifeless universe where there are no people to discover the Higgs boson.

Is the Higgs boson a boson from the Standard Model?

1. Despite the fact that the Higgs boson is from the Standard Model, there are small discrepancies indicating the existence of new physics (currently unknown).
2. There are more than one Higgs bosons, with different masses. This also suggests that there will be new theories to explore.

Only time and new data will reveal either the purity of the Standard Model and its boson or exciting new physical theories.

The model in the form of physical fields was built for a very long time by many physicists who persistently study the Universe. The development of this model began in the 70s of the twentieth century. Its essence is simple: without the Higgs boson, matter cannot have mass.

Quite recently, a long-awaited event occurred: the famous “God particle” was discovered at CERN. The prediction came true, and science moved closer to solving the mystery of the Universe. Let's try to imagine what he is like. To do this, you need to crumble a piece of polystyrene foam onto the table. If you blow on the resulting crumbs, which are analogues of elementary particles, they will easily fly apart. But if the surface of the table is covered with a layer of water, the scattering of crumbs will become difficult. In this comparison, water performs the function of the Higgs field, as if giving the crumbs some mass. And the analogue of bosons will be ripples water surface, if you blow on it. The only difference is that such a field does not affect the movement of particles, but their acceleration.

Higgs field

The Higgs field affects particles passing through it. For example, photons can pass through this field absolutely freely, but other particles - W- and Z-bosons - will slow down. Everything that has mass interacts with the Higgs field. And this field occupies the entire space of the Universe. Like all other fields, the Higgs field requires a certain particle that will carry the interaction, influencing the particles in this field. This carrier is the Higgs boson. It was experimentally discovered at the LHC on July 4, 2012 and had a mass of 125 – 126 GeV/c 2 . Without the Higgs field, the concept of the construction of matter would have turned out completely different. But even the picture of the Universe that has emerged now cannot be final and does not explain all of its properties. Cosmology states that the vast majority of matter in the Universe may consist of completely different forms of matter. The Higgs boson should help further research into understanding these shapes. And some optimistic scientists are already trying to use the discovery in practice. For example, if you somehow remove the Higgs field, then all elementary particles will lose mass. Perhaps there will be a real possibility of creating antigravity. Although, it is unknown how this could turn out, and whether this is even possible.

In the standard model, only one Higgs field is allowed, which determines all the masses of elementary particles. But extended, supersymmetric standard models (SSMs) are emerging. In these models, each particle is associated with a superpartner that has closely related properties (however, such particles have not yet been discovered). SSM already requires at least two fields, which, interacting with particles, endow them with mass. These same fields give part of the mass to superpartners. Two Higgs fields can produce five types of Higgs bosons. Of these, three have a neutral value, and two have received a charge. Neutrinos, whose masses are incomparably smaller than the masses of other particles, can be born from such interactions.

Higgs boson - a harbinger of the death of the Universe?

One of the many options for the end of the world relies specifically on the Higgs boson. The properties of this particle give our Universe an unstable state, which makes it possible for it to be absorbed by another, alternative Universe. After some time, due to quantum fluctuation, a vacuum bubble may appear, which will become an alternative Universe, and it will destroy ours. The magnitude of the mass of the discovered boson makes such a catastrophe very real. But not everything is so bad: the end of the world will happen at the speed of light, so we are unlikely to have time to realize its consequences. It is believed that this catastrophe could break out at any moment, but most likely it will unfold very far from us. So, we have a head start of several billion years.

How they opened it

The Large Hadron Collider was built to search for this particle. This is probably the most expensive project in the entire history of mankind, incorporating the latest achievements of scientific and engineering geniuses. Only grandiose ones can compare with it in cost. space projects. In an underground ring about 27 km long, hydrogen nuclei - protons - are accelerated using electric fields. Proton beams are fired in opposite directions. Accelerated to gigantic speeds, slightly less than the speed of light, protons collide with each other. The enormous energy acquired by protons is equivalent to mass, so the result of collisions of massive particles is the birth of new particles. They are very unstable and undergo rapid decay. Traces of collisions are recorded and processed by special detectors. By repeatedly studying the traces of these collisions, the Higgs boson was discovered.

The importance of the discovery of the Higgs boson for modern science is confirmed by the fact that it was called the “god particle.”