The Higgs boson is the fundamental force-carrying particle in the Higgs field, and is responsible for giving other particles their mass. This field was first proposed in the mid-1960s by Peter Higgs – after whom the particle and his colleagues are named.
The particle was finally discovered on July 4, 2012 by researchers at the Large Hadron Collider (LHC) – the world’s most powerful particle accelerator – located at the European particle physics laboratory CERN, Switzerland.
The LHC confirmed the existence of the Higgs field and the mechanism that leads to the formation of mass and thus completed the Standard Model of particle physics – our best description of the subatomic world.
Related: The Higgs boson could have kept our universe from collapsing
As scientists approach the end of the twentieth century, advances in particle physics have answered many of the questions that surround the basic building blocks of nature. However, as physicists steadily fill the particle zoo with electrons, protons, bosons and all the flavors of quarks, some burning questions remain unanswered. Among these, why do some particles have mass?
This question motivates the story of the Higgs boson.
What is the Higgs boson?
The Higgs boson has a mass of 125 billion electron volts (Opens in a new tab)– This means that it is 130 times greater than the mass of a proton, according to CERN (Opens in a new tab) . It is also free of charge with zero spin – which is the quantum mechanics equivalent of angular momentum. The Higgs particle is the only elementary particle that does not rotate.
A boson is a “force-carrying” particle that plays its role when the particles interact with each other, with the boson exchanged during this interaction. For example, when two electrons interact they exchange a photon – the force-carrying particle of electromagnetic fields.
Since quantum field theory describes the microscopic world and the quantum fields that fill the universe with wave mechanics, a boson can also be described as a wave in a field.
So, a photon is a particle and a wave that arises from an excited electromagnetic field, and the Higgs boson is the particle or “quantum aspect” that arises from the Higgs field upon excitation. This field generates mass through its interaction with other particles and the mechanism carried by the Higgs boson called the Brout-Englert-Higgs mechanism.
Why is the Higgs boson called a “God particle”?
(Opens in a new tab)
The nickname “God particle” was cemented into the Higgs boson upon its discovery, a result of the popular media. The origin of this is often associated with Nobel Prize-winning physicist Leon Lederman referring to the Higgs boson as the “damned particle” in frustration about how difficult it is to detect it.
interested in trade (Opens in a new tab) He says that when Lederman wrote a book on the Higgs boson in the 1990s, the title was “Cursed Particle” but the publishers changed this to “God particle” and a disturbing relationship was drawn with religion, which vexes physicists to this day.
However, it is difficult to overestimate the importance of the Higgs boson and the Higgs field in general, because without this aspect of nature particles would not have mass. This means no stars, no planets, and no us – something that might help ensure its hyperbolic title.
Why is the Higgs boson important?
In 1964, researchers began using quantum field theory to study the weak nuclear force (Opens in a new tab) – which determines the atomic dissolution of the elements by converting protons into neutrons – and carries its strength W and Z bosons.
The carriers of weak force must be massless, and if there is no risk of violating the principle of nature called symmetry which–just as symmetry of form ensures that it appears the same if it is flipped or turned–ensures that the laws of nature are the same but displayed. Placing mass arbitrarily on particles also caused certain predictions to go toward infinity.
However, the researchers knew that because the weak force is so strong on short-range interactions — much stronger than gravity — but so weak on longer interactions, its bosons must have mass.
The solution proposed by Peter Higgs François Englert and Robert Prout in 1964 was a new field and a way to “trick” nature into automatically breaking symmetry.
Article from CERN (Opens in a new tab)He compares this to a pencil standing on its tip – a symmetric system – that suddenly flips to indicate the preferred direction and destroys its symmetry. Higgs and his fellow physicists suggested that when the universe was born, it was filled with a Higgs field in a symmetric, but unstable state—like an unstable pencil.
The field quickly finds, in milliseconds, a stable configuration, but this in the process breaks its consistency. This gave rise to the Brout-Englert-Higgs mechanism that confers mass to the W and Z bosons.
What was later discovered about the Higgs field was that it would not only give mass to the W and Z bosons, but also give mass to many other fundamental particles. Without the Higgs field and the Brout-Englert-Higgs mechanism, all the fundamental particles would be racing around the universe at the speed of light. This theory not only explains why particles have mass, but also why they have different masses.
Particles that interact – or “couple” – with the Higgs field more strongly are endowed with greater masses. Even the Higgs boson itself gets its mass from its interaction with the Higgs field. This was confirmed by observing how the Higgs boson particles decay.
One particle that the Higgs field does not give mass is the fundamental particle of light – the photon. This is because spontaneous symmetry breaking does not happen to photons as it does to force-carrying particles such as the W and Z bosons.
This mass-giving phenomenon also applies to fundamental particles such as electrons and quarks. Particles such as protons – made of quarks – get most of their mass from the binding energy that holds their components together.
While all this fits well with the theory, the next step was to discover evidence of the Higgs field by discovering the force-carrying particle. Doing so would not be a simple task, in fact, it would require the largest experience and advanced machine in human history.
In this way, the search for the Higgs boson has pushed both particle accelerator and detector technology to their limits—with the ultimate expression of this being the Large Hadron Collider (LHC).
Discovery of the Higgs boson and the Standard Model
(Opens in a new tab)
The discovery of the Higgs boson is not just a matter of setting up a detector and waiting for one to appear. These particles only existed in the high-energy conditions of the early universe.
This means that before this particle is discovered, these high-energy conditions must be replicated and the Higgs bosons created. The LHC does this by accelerating protons to near the speed of light and smashing them together.
This creates a series of particles that quickly decompose into lighter particles. The Higgs boson decays too quickly to be detected, and instead was determined by detecting particle decay that indicates the presence of a particle without a spin and matches theoretical predictions for this missing boson.
The particle was detected by both the LHC ATLAS reagent and the Compact Muon Solenoid (CMS) reagent.
The detection of the Higgs boson was announced at CERN in Geneva on July 12, 2012. It took until March of the following year to confirm that the detected particle was indeed the Higgs boson.
By detecting this particle, predicted by the Standard Model, the discovery of the Higgs boson completed this picture of the subatomic world. There are still mysteries behind this theory such as the nature of dark matter that the Higgs boson – through its unique properties – could help solve.
Higgs boson after 2012
The year following the discovery of the Higgs boson, Peter Higgs and François Englert were awarded the 2013 Nobel Prize in Physics, for their Higgs field theory.
Nobel Committee (Opens in a new tab) He wrote of the award: “For the theoretical discovery of a mechanism that contributes to our understanding of the origin of the mass of subatomic particles, which was recently confirmed by the discovery of the expected fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider.”
The discovery of the Higgs boson may have completed the Standard Model, but that wasn’t the end of the investigation of this elusive particle. One of the major discoveries made since 2012 included confirmation of the Higgs decay.
The investigation of this elusive particle will be further investigated during the LHC’s 3 run, especially when the high-luminosity upgrade of the particle accelerator is completed in 2029. (Opens in a new tab).
This will allow the LHC to make more collisions, providing researchers with more opportunities to discover exotic physics, including phenomena that go beyond the Standard Model.
The European Organization for Nuclear Research (CERN) estimates that after upgrading each year, the accelerator will create 15 million of these particles. This compares with the 3 million Higgs bosons created by the Large Hadron Collider in 2017. This may be key to discovering other “flavors” of the Higgs boson.
Theories that go beyond the Standard Model of particle physics also predict up to five different types of Higgs bosons that can be produced more frequently than the basic Higgs boson. Even before the modernization, scientists had already provided us with tantalizing evidence of the “magnetic Higgs boson”.
The discovery of the Higgs boson completed what is known as the Standard Model of particle physics. CERN . explains (Opens in a new tab) What this framework tells us about the subatomic world. Learn more about the Higgs boson with this article from the US Department of Energy (Opens in a new tab). Explore some frequently asked questions (Opens in a new tab)About the Higgs boson with CERN.
Higgs boson, CERN, https://home.cern/science/physics/higgs-boson (Opens in a new tab)
Higgs boson, Department of Energy, https://www.energy.gov/science/doe-explainsthe-higgs-boson (Opens in a new tab)
What distinguishes the Higgs boson? , CERN, https://home.cern/science/physics/higgs-boson/what
Higgs. P., BROKEN SYMMETRIES AND THE MASS OF GAUGE BOSONS, physical review letters, And the [https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.13.508 (opens in new tab)]
Peter W. Higgs, Nobel Prize, https://www.nobelprize.org/prizes/physics/2013/higgs/facts/ (Opens in a new tab)
LHC High Brightness, CERN, https://home.cern/science/accelerators/high-luminosity-lhc (Opens in a new tab)