What is the Higgs Boson?

What is this thing we keep hearing about – the Higgs Boson, and why is it important?

It’s been said that the best way to learn is to teach. And so, today I’m going to explain everything I can about the Higgs boson. And if I do this right, maybe, just maybe, I’ll understand it a little better by the end of the episode.

I’d like to be clear that this video is for the person whose eyes glaze over every time you hear the term Higgs boson. You know it’s some kind of particle, Nobel prize, mass, blah blah. But you don’t really get what it is and why it’s important.

First, let’s start with the Standard Model. These are essentially the laws of particle physics as scientists understand them. They explain all the matter and forces we see all around us. Well, most of the matter, there are a few big mysteries, which we’ll discuss as we get deeper into this.

But the important thing to understand is that there are two major categories: the fermions and the bosons.

Bosons, fermions and other particles after a collsion. Credit: CERN
Bosons, fermions and other particles after a collsion. Credit: CERN

Fermions are matter. There are the protons and neutrons which are made up of quarks, and there are the leptons, which are indivisible, like electrons and neutrinos. With me so far? Everything you can touch are these fermions.

The bosons are the particles that communicate the forces of the Universe. The one you’re probably familiar with is the photon, which communicates the electromagnetic force. Then there’s the gluon, which communicates the strong nuclear force and the W and Z bosons which communicate the weak nuclear force.

Mystery number 1, gravity. Although it’s one of the fundamental forces of the Universe, nobody has discovered a boson particle that communicates this force. So, if you’re looking for a Nobel Prize, find a gravity boson and it’s yours. Prove that gravity doesn’t have a boson, and you can also get a Nobel Prize. Either way, there’s a Nobel Prize in it for you.

Credit: PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group
Credit: PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group

Again, this is the Standard Model, and it accurately describes the laws of nature as we see them around us.

One of the biggest unsolved mysteries in physics was the concept of mass. Why does anything have mass at all, or inertia? Why does the amount of physical “stuff” in an object define how easy it is to get moving, or how hard it is to make it stop?

In the 1960s, physicist Peter Higgs predicted that there must be some kind of field that permeates all of space and interacts with matter, sort of like a fish swimming through water. The more mass an object has, the more it interacts with this Higgs field.

And just like the other fundamental forces in the Universe, the Higgs field should have a corresponding boson to communicate the force – this is the Higgs boson.

The field itself is undetectable, but if you could somehow detect the corresponding Higgs particles, you could assume the existence of the field.

Cross-section of the Large Hadron Collider where its detectors are placed and collisions occur. LHC is as much as 175 meters (574 ft) below ground on the Frence-Swiss border near Geneva, Switzerland. The accelerator ring is 27 km (17 miles) in circumference. (Photo Credit: CERN)
Cross-section of the Large Hadron Collider where its detectors are placed and collisions occur. LHC is as much as 175 meters (574 ft) below ground on the Frence-Swiss border near Geneva, Switzerland. The accelerator ring is 27 km (17 miles) in circumference. (Photo Credit: CERN)

And this is where the Large Hadron Collider comes in. The job of a particle accelerator is to convert energy into matter, via the formula e=mc2. By accelerating particles – like protons – to huge velocities, they give them an enormous amount of kinetic energy. In fact, in its current configuration, the LHC moves protons to 0.999999991c, which is about 10 km/h slower than the speed of light.

When beams of particles moving in opposite directions are crashed together, it concentrates an enormous amount of energy into a tiny volume of space. This energy needs somewhere to go so it freezes out as matter (thanks Einstein). The more energy you can collide, the more massive particles you can create.

And so, in 2013, the LHC allowed physicists to finally be able to confirm the presence of the Higgs Boson by tuning the energy of the collisions to exactly the right level, and then detecting the cascade of particles that occur when Higgs bosons decay.

Because the right particles are detected, you can assume the presence of the Higgs boson, and because of this, you can assume the presence of the Higgs field. Nobel prizes for everyone.

Particle collision. Credit: CERN
Particle collision. Credit: CERN

I said there were a few mysteries left; gravity was one, of course, but there are a few more. The reality is that physicists now know that the matter I described is really just a fraction of the entire Universe. Cosmologists estimate that just 4% of the Universe is the normal baryonic matter that we’re familiar with.

Another 23% is dark matter, and a further 73% is dark energy. So there are still plenty of mysteries to keep physicists busy for years.

And so, in 2013, the Large Hadron Collider finally turned up the particle that physicists had predicted for 50 years. The last piece of the Standard Model was finally proven to exist, and we’re closer to understanding what 4% of the Universe is. The other 96% (oh, and gravity), are still a total mystery.

Physicists are cranking up the LHC to higher and higher levels of energy, to search for other particles, to understand dark matter, and see if they can generate microscopic black holes. This mighty instrument has plenty more science to reveal, so stay tuned.

That’s the Higgs Boson in a nutshell. Let me me know if there are other concepts in particle physics you’d like to talk about. Put your ideas into the comments below.

15 Replies to “What is the Higgs Boson?”

  1. Now I get it. Although I’ll go one step further. Higgs Boson has no “particles’, no visible mass of its own. Its ‘mass’ (for lack of a better word) is intangible in all & any way, shape or form. It exerts force proportionate to the mass sliding thru it. Sort of like a minnow and whale swimming in the same general area. However, as a mass propelles through the boson, the mass’s momentum leaves a vortex behind that keeps pushing it, moving it in the same forward direction until (when and if) another force(s) bumps into it.
    Nothing new here. It’s like geese flying in formation using the energy the geese in front leave behind.
    P.S.
    From a human stand point This (Hypothetical) ‘Dark Matter’ will never be able to be measured or placed into any percentile of anything.
    The wind can’t be seen but it can be felt. Dark Matter will NEVER be seen or be felt but we’re up to our necks in it. it isn’t made up of any particle of any size or polarity.

    1. Scott, there is a fundamental difference between using c**2 as a mathematical constant used to calculate the magnitude of energy found in matter versus the actual, physical limit of speed represented by the constant c. c**2 shows how energy greatly increases with mass, c does not change. Therefore, c**2 does not violate the value of c in any way. Hope that helps.

    2. Interesting position, posted with much apparent confidence. A reply evokes too many questions to list: just two – 1. If the Higgs boson has no mass, was the mass of 127 GeV assigned only because that was the calculated energy that manifested it? and 2. a.Why do you think the DM will never be seen, felt (non-anthropomorphically) or measured? b. Is it unattached subatomic matter?

      Thanks

  2. Thanks for the informative discussion about the Higgs. You are helping us novices understand what it is.

    I have a general question about E=MC2. Hopefully you don’t mind me asking it here. Here goes: How can the Speed of Light be squared? I thought that a corollary of Einstein’s work is that the Speed of Light is the Speed Limit; there is no going faster. However, he squares the Speed of Light in his famous equation. So, does this mean that the Speed of Light can be improved? Thanks.

    1. Scott, there is a fundamental difference between using c**2 as a mathematical constant used to calculate the magnitude of energy found in matter versus the actual, physical limit of speed represented by the constant c. c**2 shows how energy greatly increases with mass, c does not change. Therefore, c**2 does not violate the value of c in any way. Hope that helps.

  3. Your saying, the Higgs boson exists in the Higgs field that interacts with matter and thus gives mass to matter, must follow the scientific criterion of 21st century and not follow philosophical and protoscientific practices of ancient world.
    If protons entering the collision (LHC) got mass thanks to everywhere present Higgs bosons then Higgs bosons are not entering into the balance of mass and energy of that collision. After collision, there must be equal amount mass and energy in products as in entry. Only, if they noticed more mass and energy in products then the scientific world may accept that Higgs boson was found. Science is there where mass and energy cannot be created or destroyed, only modified in form.
    If you are serious in proclaiming scientific truth then you must not omit at Higgs boson that they discovered really the part (the particle) having extreme density never before detected. This is logical expectation of that collision since we know that extreme density of objects come to exist in crashes when they had a high speed. If we would consider the crash of objects (protons) having a speed almost twice of the speed of light into a standing block then products of such a crash must have changed (deformed) their volumes.
    Please, do not violate physics by witchcraft (materializing spirits and mathematics) and by pseudo-physics conclusions (creating particles by not respecting the balance of collisions).

  4. Thank you for that “energy freezes out as matter” line. Just a retired high school chem/physics teacher here, so that idea of thinking of matter as precipitated energy clicks for me big time. Am I correct in thinking the concept extends to nucleogenesis in supernovae? The energy is so high that matter essentially precipitates out as a low-volume form of energy?

  5. What if we’re looking at gravity all wrong. We know it is intimately tied to mass somehow. We also know it is indistinguishable from acceleration. We also know that most of the mass of matter comes from the binding energy within matter, with the final bit coming from the Higgs field. Also, tantalizing theoretical work done using Scale Symmetry theory has modeled the emergence of all massed particles and their forces from the massless particles and their forces interacting alone. So what if gravity truly is only acceleration, with the Higgs field being the start of a cascade to mass-fulness? We know that massless particles naturally travel at the speed of light, but no massed particles can ever reach these speeds. What if the mechanism of interaction between photons, mesons, neutrinos that lead to the emergence of mass is the initial interactions with the Higgs fields, and gravity is akin to an inertial “impulse” impeded by the Higgs field, rather than gravity being a particle and field configuration as everyone supposes? Perhaps we already have a unified field theory and no one knows it because we’ve assumed gravity must be a classical force when in fact it is not…

    1. I thought Einstein resolved the question with his general theory that gravity is not a force but a mass induced distortion of space time. Hence there is no need to search for a gravity boson. There is none.

  6. How can a single type of Higgs account for particles with different masses? Are some particles made up of multiple Higgs or do some Higgs have different masses? Are there any particles that have less mass than the Higgs, if so how?

    1. Different particle couple to the Higgs fields with different strengths– hence they have different masses. The Higgs field is constant, everywhere (except at LHC). It is not zero, but it has 0 Higgs Bosons: that is the so-called vacuum state. At LHC there is enough energy to excite the Higgs Field to a state with 1 Higgs Boson (it is massive because it also couples to the Higgs Field).

      An analogy would be the Electromagnetic Field: it’s vacuum state is 0 with 0 photons. The 1st excited state has 1 photon.

  7. First of all – Thank you! An excellent and simple way to understand the Higgs Boson and the other terms often used in reference to it. Maybe you can help me….

    I have a very serious question – I am not joking – regarding Einstein’s famous equation.

    Either I am understanding something wrong or his iconic equation is not worth the paper it was written on. By definition:

    In physics, mass–energy equivalence explains the relationship between mass and energy. It states every mass has an energy equivalent and vice versa—expressed using the formula

    E = mc2

    where E is the energy of a physical system, m is the mass of the system, and c is the speed of light in a vacuum (about 3×108 m/s). In words, energy equals mass multiplied by the speed of light squared.

    The way I understand this claim, then one gram of cotton candy has as much energy as one gram of lead. If I understand the definition of the equation properly, the cotton candy/lead equivalence is not true.

    If the “m” expressed the molecular/atomic bonding energy of the matter in question I would agree with it – as long as that expression truly reflected the level of molecular/atomic bonding energy.

    Maybe I am missing something.

    Any clarification would be greatly appreciated.

  8. These particles are so small, so it cannot be hold in a container. I am curious if these particles can be redirected to rotate around a stripped neutrons

    If it so happens to rotate we can add more of the same continuously so that they are in large numbers together, to know its properties

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