Crash Course in the Higgs

Flummoxed by the Higgs? Here's what you need to know to understand why this discovery was a big deal.

Few were surprised by this year’s recipients of the Nobel Prize in Physics: François Englert and Peter W. Higgs, who in 1964 independently proposed a mechanism for how fundamental particles acquire mass. That mechanism, now called the Higgs field (and its particle, the Higgs boson), was confirmed last year by the discovery of a Higgs particle at the CERN laboratory outside Geneva.

The Higgs is a bit outside S&T’s astro-focused purview — although that didn’t stop us from waxing philosophic about the discovery’s implications. But we’re a curious bunch, and we know that our readers are, too. So I’ve put together some info we’ve found helpful when poking around for insights into what this Higgs thing is.

If you want to understand the Higgs field in a nutshell, you’re in luck: TED-Ed put together an entertaining 3-minute video, which explains the Higgs with a cocktail party analogy. You can watch the video below, or on YouTube. (Note the Nobel prediction at the end: this video is from several months ago.)

One thing that’s often lost in these discussions: the Higgs field isn’t the only source of all particles’ masses. It is the source for the rest mass of many fundamental particles, such as quarks, which are the subatomic particles that make up protons and neutrons. But as “composite particles,” protons and neutrons mostly take their masses from the energy holding their constituent quarks together. So the Higgs is only responsible for about 1% of the mass of everyday stuff.

If the Higgs field only explains a tiny fraction of everyday stuff’s mass, why do we care? Because before the Higgs field, particle physics couldn’t explain why many fundamental particles have mass. And that was a big problem: a massless electron means no atoms. No atoms means stars, planets, and creatures go *poof.* Scientists don’t like things that go *poof.*

CERN has a good blog on what the Higgs boson is. There’s another intriguing blog that explains why the Higgs and gravity aren’t related. And the Nobel Prize people put out a wealth of information with the announcement: if you scroll down below the Nobel press release, there’s a file “for the public” and another file with “scientific background.” Pick your poison.

And congratulations to the winners, and to the hundreds of people who made the discovery possible! Englert and Higgs couldn't have won without the engineers, physicists, and students who worked hard at CERN.

10 thoughts on “Crash Course in the Higgs

  1. Peter WilsonPeter W

    Two photons collide. A proton and antiproton result. First there is no mass there; then there is. “In our analogy of the party, all particles (have zero mass) until they enter the room. It is the interaction with crowd that causes them to gain mass. Mass comes from interaction with the field,” Don Lincoln concludes. So the two photons “enter the room,” resulting in six quarks that “interact with the field,” and therefore have mass? I’m still confused.

  2. Robert-CaseyRobert Casey

    maybe François Englert and Peter W. Higgs have CERN display their Nobel prize, say in a trophy case, next to the soccer trophies, in the front lobby, saying "Without all your help, we wouldn’t have won this. Thank you". As the people of CERN did a lot of work to help discover it. 🙂

  3. Elezer Puglia

    I agree that, as a measure of gratitude for CERN’s absolutely magnificent efforts, Higgs and Englert could just do such a thing as proposed. However, it should be noted that, as a matter of fact, the gigantic CERN collider was built **for the purpose** of detecting the evidence for the existence of the Higgs field and bosons. Without the theoretical groundbreaking work, they wouldn’t know where to start looking. This is also the reason why, more often than not, theorists get Nobel Prizes in Physics, rather than experimentalists.

  4. Camille M. CarlisleCamille Carlisle

    Peter, I think your confusion stems from the combination of two separate ideas. Here all the particles are not photons. The point is that a fundamental particle has a particular mass based on its interaction with the Higgs field — the mass is a result of this interaction/relationship, not an intrinsic quality the particle has in isolation. So what makes a photon a photon (mass-wise) is that it doesn’t interact with the Higgs field. A photon, a quark, and an electron will all interact with the field in unique ways, and that’s what gives the particles their unique masses. It’s kind of like how a person walking through a room of preschoolers will attract a certain number of kids based on who they are. Some pass through unimpeded, and others end up with kids glommed onto both legs. It’s not that they’re all the same type of person before entering; it’s that their kid-attraction ability manifests only when in the presence of kids. (That’s a really bad analogy, but I hope it helps. Maybe one of our readers will have a better one!)

  5. Bruce

    I liked that kids glomming on analogy just fine Camille. Together with your article and the video included therein my understanding of the Higgs field has grown exponentially. Peter, in your photons colliding case the total mass changes, but mass is not conserved in sub-atomic particle interactions, energy is. (I’m sure you knew this.) But the inverse of the proton + antiproton annihilation reaction is interesting. First there is light, and then there is matter (and antimatter). But this posses no issue for the Higgs field. In the analogy the particles enter the room upon their creation.

  6. John AndersonJohn Anderson

    In David Griffiths’ advanced undergraduate level textbook, Introduction to Elementary Particles, he describes the Higgs Mechanism as “diabolically subtle”. The analogies used to explain the Higgs in popular science literature may be helpful but they are horribly incomplete.

    The long chain of logical steps to understand the Higgs goes back to the Principle of Least Action and Lagrangian Classical Mechanics. Particle physics uses a quantum mechanical Lagrangian and expects it to remain invariant under certain changes such as swapping a neutrino and an electron (both of which are left-handed) but it isn’t invariant. This doublet is mathematically described by a group, SU(2). But Nature has broken the symmetry. The weak force particles have acquired mass which isn’t supposed to happen in a well behaved ‘gauge theory’.

    Higgs and Co. play mathematical tricks to try to restore the symmetry. Kerson Huang describes the steps in a book for the general audience, “Fundamental Forces of Nature” and this is where I lose the trail. “Replace mass term by a complex scalar field phi, ϕ, which transforms as a doublet under SU(2): where the first component, phi-plus, carries positive electric charge, and the second component, phi-sub 0 is neutral. We can then combine the doublet, phi, with the left-handed electron to produce an invariant under SU(2). The mass is then proportional to second component of the doublet, phi-sub 0. The complex scalar field phi, ϕ ,is called the Higgs field.”

    Science writers suspect that the general reader doesn’t have the background or patience to step through a real explanation and I’m not sure many general readers want to tackle a real explanation. I’m still struggling to understand what Peter Higgs has wrought.

  7. Bruce

    Wow. Thanks for sharing that, but wow John. That’s the deepest comment that I can remember anyone ever posting here. But it put me in mind of one of my favorite quotes, appropriately from another winner of the Nobel Prize for Physics, Paul Dirac: “It seems to be one of the fundamental features of nature that fundamental physical laws are described in terms of mathematical theory of great beauty and power, needing quite a high standard of mathematics for one to understand it. You may wonder: Why is nature constructed along these lines? One can only answer that our present knowledge seems to show that it is so constructed. We simply have to accept it. One could perhaps describe the situation by saying that God is a mathematician of a very high order, and He used very advanced mathematics in constructing the universe. Our feeble attempts at mathematics enable us to understand a bit of the universe, and as we proceed to develop higher and higher mathematics we can hope to understand the universe better.”

  8. Dusty

    So… the Higgs boson passes through the crowd, and gains mass. I can understand that. What if a whole bunch of bosons pass through the same space? Is there the same gain in mass for each subsequent boson (i.e., the available "mass" is unlimited), or do subsequent bosons at some point run out of mass to gather and subsequently register differently when their mass is measured? Or does this "mass field" (the room) simply fill-in as would a fluid?

  9. Bruce

    Dusty, to my very limited understanding, it’s not the Higgs boson particle that provides mass to other particles, it’s the Higgs field that does so. In the real world these particles don’t really exist, except very rarely for the briefest moment inside the most powerful particle accelerators, after which they instantly decay into lighter particles. But since it was proven that the Higgs boson can exist even if only for a moment, it demonstrates that the Higgs field theory is valid, as far as we know.

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