To celebrate the publication of The Particle at the End of the Universe, here’s a cheat sheet for you: mind-bending facts about the Higgs boson you can use to impress friends and prospective romantic entanglements.
1. It’s not the “God particle.” Sure, people call it the God particle, because that’s the name Leon Lederman attached to it in a book of the same name. Marketing genius, but wildly inaccurate. (Aren’t they all God’s little particles?) As Lederman and his co-author Dick Teresi explain in the first chapter of their book, “the publisher wouldn’t let us call it the Goddamn Particle, though that might be a more appropriate title, given its villainous nature and the expense it is causing.”
2. Nobel prizes are coming. But we don’t know to whom. The idea behind the Higgs boson arose in a number of papers in 1963 and 1964. One by Philip Anderson, one by Francois Englert and Robert Brout (now deceased), two by Peter Higgs, and one by Gerald Guralnik, Richard Hagen, and Tom Kibble. By tradition, the Nobel in Physics is given to three people or fewer in any one year, so there are hard choices to be made. (Read Chapter 11!) The experimental discovery is certainly Nobel-worthy as well, but that involves something like 7,000 people spread over two experimental collaborations, so it’s even more difficult. It’s possible someone associated with the actual construction of the Large Hadron Collider could win the prize. Or someone could convince the Nobel committee to ditch the antiquated three-person rule, and that person could be awarded the Peace Prize.
3. We’ve probably discovered the Higgs, but we’re not completely sure. We’ve discovered something — there’s a new particle, no doubt about that. But like any new discovery, it takes time (and in this case, more data) to be absolutely sure you understand what you’ve found. A major task over the next few years will be to pin down the properties of the new particle, and test whether it really is the Higgs that was predicted almost five decades ago. It’s better if it’s not, of course; that means there’s new and exciting physics to be learned. So far it looks like it is the Higgs boson, so it’s okay to talk as if that’s what we’ve discovered, at least until contrary evidence comes in.
4. The Large Hadron Collider is outrageously impressive. The LHC, the machine in Geneva, Switzerland, that discovered the Higgs, is the most complicated machine ever built. (Chapter 5.) It’s a ring of magnets and experimental detectors, buried 100 meters underground, 27 kilometers in circumference. It takes protons, 100 trillion at a time, and accelerates them to 99.999999% the speed of light, then smashes them together over 100 million times per second. The beam pipe through which the protons travel is evacuated so that its density is lower than you would experience standing on the Moon, and the surrounding superconducting magnets are cooled to a temperature lower than that of intergalactic space. The total kinetic energy of the protons moving around the ring is comparable to that of a speeding freight train. To pick one of countless astonishing numbers out of a hat, if you laid all the electrical cable in the LHC end-to-end it would stretch for about 275,000 kilometers, enough to wrap the Earth almost seven times.
5. The LHC was never going to destroy the world. Remember that bit of scaremongering? People were worried that the LHC would create a black hole that would swallow the Earth, and we would all die. (It was never quite explained why the physicists who built the machine would be willing to sacrifice their own lives so readily.) This was silly, mostly because there’s nothing going on inside the LHC that doesn’t happen out there in space all the time. There was a real setback on September 19, 2008, when a magnet kind of exploded, but nobody was hurt. The current casualty list from the LHC mostly consists of people’s favorite theories of new physics, which are continually being constrained as new data comes in.
6. The Higgs boson isn’t really all that important. The boson is just some particle. What’s important is something called the Higgs mechanism. What really gets people excited is the Higgs field, from which the particle arises. Modern physics — in particular, quantum field theory — tells us that all particles are just vibrations in one field or another. The photon is a vibration in the electromagnetic field, the electron is a vibration in the electron field, and so on. (That’s why all electrons have the same mass and charge — they’re just different vibrations in the same underlying field that fills the universe.) It’s the Higgs field, lurking out there in empty space, that makes the universe interesting. Finding the boson is exciting because it means the field is really there. This is why it’s hard to explain the importance of the Higgs in just a few words — you first have to explain field theory!
7. The Higgs mechanism makes the universe interesting. If it weren’t for the Higgs field (or something else that would do the same trick), the elementary particles of nature like electrons and quarks would all be massless. The laws of physics tell us that the size of an atom depends on the mass of the electrons that are attached to it — the lighter the electrons are, the bigger the atom would be. Massless electrons imply atoms as big as the universe — in other words, not atoms at all, really. So without the Higgs, there wouldn’t be atoms, there wouldn’t be chemistry, there wouldn’t be life as we know it. It’s a pretty big deal.
8. Your own mass doesn’t come from the Higgs. We were careful in the previous point to attribute the mass of “elementary” particles to the Higgs mechanism. But most of the mass in your body comes from protons and neutrons, which are not elementary particles at all. They are collections of quarks held together by gluons. Most of their mass comes from the interaction energies of those quarks and gluons, and would be essentially unchanged if the Higgs weren’t there at all. So without the Higgs, we could still have massive protons and neutrons, although their properties would be very different.
9. There will be no jet packs. People sometimes think that since the Higgs has something to do with “mass,” it’s somehow connected to gravity, and that by learning to control it we might be able to turn gravity on and off. Sadly not true. As above, most of your mass doesn’t come from the Higgs field at all. But even putting that aside, there’s no realistic prospect of “controlling the Higgs field.” Think of it this way: it costs energy to change the value of the Higgs field in any region of space, and energy implies mass (through Einstein’s famous E = mc2). If you were to take a region of space the size of a golf ball and turn the Higgs field off inside of it, you would end up with an amount of mass larger than that of the Earth, and create a black hole in the process. Not a feasible plan. We haven’t been looking for the Higgs because of the promise of future technological applications — it’s because we want to understand how the world works.
10. The easy part is over. The discovery of the Higgs completes the Standard Model; the laws of physics underlying everyday life are completely understood. That’s pretty impressive; it’s a project that we, as a species, have been working on for at least 2,500 years, since Democritus first suggested atoms back in ancient Greece. This leaves plenty of physics that we don’t yet understand, from dark matter to the origin of the universe, not to mention complicated problems like turbulence and neuroscience and politics. Indeed, we’re hoping that studying the Higgs might provide new clues about dark matter and other puzzles. But we do now understand the basic building blocks of the world we immediately see around us. It’s a triumph for human beings; the future history of physics will be divided into the pre-Higgs era and the post-Higgs era. Here’s to the new era!
Are Higgsless-universe electrons really massless? There’s no mass introduced by mixing with massive hadronic states?
So if it’s going to take a few years before we know for sure whether the recent particle is in fact the original Higgs, wouldn’t it make sense to wait until then to hand out Nobels for it?
I’m confused on #8 and #9 – are we not made of quarks – which would not exist without mass? When I look up mass and gravity on wikipedia both mention that they sort of help to define each other. I thought mass was the characteristic of how a particle interacts with gravity. The Higgs field and Higgs boson interact with some particles that allow them to be affected by gravity. So without the quality of mass that we get from the Higgs, how does a person exist? What does the Higgs field actually do if it’s possible to have massive protons and neutrons without it?
I just fired up my Kindle and there was your book that I pre-ordered. But I first have to finish your Mysteries of Modern Physics course and the new J.K. Rowling novel that I started. And there’s this thing about having to work for a living. Busy, busy.
Sean,
is there any connection between Higgs boson/Higgs field and theories of neutrino masses and mixing
(such as see-saw models)?
To me, the latter seems completely disconnected from theories of EW symmetry breaking or BSM physics, but maybe I am just ignorant.
I think the important extension that we can take from the alleged discovery of the higgs particle/field is that it might help explain the asymmetry that allowed “normal matter” to prevail over anti-matter. “CP violation in B_s mixing from heavy Higgs exchange” is an extremely interesting bit of theory in which interaction with the higgs field is what leads to a preferential decay of particles such as the B meson to normal matter as opposed to anti-matter. I particularly like the discussion this paper has generated because it grants just as much validity to the Supersymmetry theory as it does to the now complete-ish Standard Model. It’s even possible that there is an entire “family” of Higgs type particle/field mechanisms, each with a slightly differing energy mass and charge.
Since the Nobel Peace Prize has been awarded to a non-person (the European Union), perhaps the physics prize can be awarded to the LHC itself?
Question about #7 above
“The laws of physics tell us that the size of an atom depends on the mass of the electrons that are attached to it — the lighter the electrons are, the bigger the atom would be.” This statement totally confuses me, because it sounds like you are saying that an atom of Uranium has lighter electrons than an atom of helium.
I was taught that the size (mass) of an atom depends on the number of protons, electrons and neutrons in it, not the mass of the electrons.
The Higgs mechanism suggests how fundamental particles might gain mass, but here is still a problem. The mechanism does not suggest how fundamental particles obtain the CORRECT amount of mass (inertia). For example, an electron has energy of 511,000 eV. If it was possible to confine this much energy as light trapped in a hypothetical reflecting box, that much confined light would exhibit a specific amount of inertia (see http://onlyspacetime.com/, chapter 1 ). It would be a violation of the conservation of momentum if an electron with energy of 511,000 eV had a different amount of inertia as the same amount of energy in the form of confined light. The Higgs mechanism leaves a lot of unanswered questions.
@8 Brett Sampson
“Bigger” as in size. It would be larger, not more massive (in fact, it would be lighter!).
Doug, Let me attempt to explain:
Up and Down quarks have 2.4 and 4.8 MeV of mass respectively. The proton (2 Up and 1 Down) has about 938 MeV of mass. IOW, 1% of a proton’s mass comes from the valence quark’s mass which is imparted by the Higgs field. The remainder of the mass comes from relatavistic effects on the gluons and ‘sea quarks’ (quark/anti-quark virtual pairs from quantum fluctuations) within the proton.
X– Electrons would still have some mass, but it would be incredibly small. Atoms would be of astronomical size at a minimum.
Curious Wavefunction– They might very well wait. But the new particle is very higgs-like, and the inventors aren’t getting any younger.
Doug– Gravity and mass are very different. Mass would exist even without gravity at all; it’s the resistance you feel when you push on something to try to get it moving. Quarks could exist even if they were massless. Protons and neutrons would be very different (actually, there would be many more observable baryons, since all the quarks would be massless), but their mass would be essentially the same, since it’s mostly from the strong interactions.
Shantanu– There are connections, but since we don’t know a lot about the real origin of neutrino masses, it’s hard to say.
Brett– That’s because your teachers assumed that electrons have a fixed mass (which they do, outside thought-experiment land). In the real world, uranium atoms are bigger (in size, not in mass) than hydrogen atoms because they have more electrons, therefore the outermost electrons fill shells that are larger. But if we imagine turning down the mass of the electrons, all of those atoms would get bigger. See: http://en.wikipedia.org/wiki/Bohr_radius
Fun fact #11: The entire time that we’ve been searching for the Higgs, everything in the universe has been hurtling away from us, getting faster the closer we got…
Sean, about your #7:
if quarks were massless the proton would not be stable, decaying into a neutron. so there wouldn’t even be any nuclei around which electrons could orbit…
>enough to wrap the Earth almost seven times.
This number rang a bell with me — a little while back I computed how many times light could go around the Earth in a second. The answer was a bit over seven. So… the LHC has just under a light-second of electrical cable.
@14 chris:
“if quarks were massless the proton would not be stable, decaying into a neutron. so there wouldn’t even be any nuclei around which electrons could orbit…”
This is an interesting observation. Note that it holds only for free protons, so only hydrogen atoms could not exist. Heavier nuclei can provide dynamical stability for the proton, just as they do for the neutron (a free neutron is unstable, but a neutron bound in a nucleus is stable, in most cases).
Of course, I agree that — if quarks are maseless then proton is unstable, and consequently hydrogen atoms cannot exist — is an argument enough. 😉
🙂
Marko
@12 Sean:
“Doug– Gravity and mass are very different. Mass would exist even without gravity at all; it’s the resistance you feel when you push on something to try to get it moving.”
Sean, say again? What happened to the equivalence principle? Inertial mass equals gravitational mass?
Are you trying to discredit your own knowledge of general relativity in the eyes of the public? 🙂
Btw, strictly speaking, the gravitational “charge” is energy, while mass is just one form of energy (among many others). So simply put, gravity can exist without mass (think gravitational field of a photon), but mass cannot exist without gravity (mass is a form of energy, which is a source of the gravitational field).
HTH, 🙂
Marko
Dear Sean Carroll, a very large number of other physicists would agree with me that this statement is untrue:
“The laws of physics underlying everyday life are completely understood.”
This misleads the pubic, who often trust someone like you. In your follow up posts that try to defend the statement, you later change completely what you are saying, and remove the central phrase ‘are completely understood’. Instead you suddenly just say that we’ll still believe in electrons in 1000 years time. That is a totally different statement, and many would agree with it. But I’m going to take apart your original statement, which you’ve posted here, and in other places, and which you seem not to have retracted.
http://blogs.discovermagazine.com/cosmicvariance/2010/09/23/the-laws-underlying-the-physics-of-everyday-life-are-completely-understood/
If this is so, then no doubt you will be able to explain to us right here how the large-scale world we see around us emerges from the quantum world. To understand the laws underlying the physics of everyday life, we need to understand that, and in current physics we have absolutely no idea how it does.
To understand quantum mechanics, we need to know what the wave function actually IS, we don’t know what it is at all. The wave function is central to the laws of physics. We know some of these laws, but we don’t understand them. We have spent 80 years trying to understand what the wave function is. We will not understand the laws underlying the physics of everyday life until we know what the wave function is.
This is one of a long list of things that are not understood about the laws underlying physics. It means that there’s no way you could get the world we see around us to come out of the understanding we have at present. And that’s the acid test – could you construct the world we find around us out of the physics that we currently understand? Of course you couldn’t, you couldn’t get near it. There are questions relating to time, gravity, and many other areas that would make it impossible, because these things are simply not understood. You know how stuck we are in trying to understand some of these areas, so tell the public. Physicists know that already.
So please, do the decent thing, and retract your statement right here. What you say is simply false, and very misleading to the public. Also, your tone is arrogant and seems somewhat drunk on power, as if the progress we’ve made in physics somehow reflects on you. Ironically, what you say means that it doesn’t, because the scientific enterprise lives and breathes a very different tone, and a very different attitude to the self-congratulatory one you exude in what you write. It is one of open-mindedness, and of admitting what we don’t know, which allows progress to be made. Your attitude is one that tends to hold progress back, by failing to admit what we don’t know.
#9: Stochastic electrodynamics’ vacuum energy is spatially uniform, canceling re gravity at Earth’s center.
http://www.calphysics.org/
Rigorously derived. So?
Absent Einstein, Ernest O. Lawrence’s MeV cyclotron energies for electrons (0.511 MeV/c^2 rest mass) are Newtonian disaster. Curve-fit or rewrite physics. Yang and Lee. Rigor does not repair defective postulates.
Massless boson photons see zero vacuum anisotropy. Symmetry breakings patch parity violations for fermionic matter in isotropic vacuum. A trace chiral background, trace anisotropy, acts upon matter. 1) Noetherian connection between vacuum isotropy and angular momentum conservation is trace leaky for matter, MOND’s 1.2×10^(-10) m/sec^2 Milgrom acceleration. No dark matter detection. 2) Opposite shoes mount a vacuum left foot with different energies. They locally vacuum free fall along non-identical minimum action trajectories, trace violating the Equivalence Principle. Crystallography’s opposite shoes are enantiomorphic space groups. arXiv:1207.2442 loaded with single crystal P3(1)21 versus P3(2)21 α-quartz test masses ends parity “violations.” Look.
Now that there’s actual evidence of existence, the name “God particle” becomes even less appropriate.
@18 Yes, we can construct the everyday world from QM and relativity. We understand how it leads to atoms, how atoms lead to molecules, and how molecules lead to large scale structures. It requires no understanding of the wave function’s epistemology to describe a water molecule. We have a separate theory of gravity, space, and time, that works for everything in everyday life and then some. When one says “we completely understand the physics of everyday life,” it is implicitly acknowledging that there are still some large questions we can’t answer, but that every question you could ask about something that directly affects a person’s daily routine (and don’t say: but the exact origin of the Universe has a huge effect; true, but it’s not a mundane daily thing) has an answer.
“People were worried that the LHC would create a black hole”
The Springfield Subatomic Supercollider DID create a black hole. I saw it on TV. It must be true.
I’ve seen a lot of articles on the interwebs in the past few days talking about the predicted Higgs would be a nightmare because that means we are seriously missing something from our understanding of nature since dark matter and dark energy are not included in the standard model. So why is one side completely freaked out by this and the other side is happy? If it does turn out that this is a strict higgs exactly as predicted, then does that support the belief that dark matter and dark energy are misunderstood phenomena and not unidentified particles?
I’ve also been reading over the Kyoto conference and it sounds reassuring that the parameters for new physics are being narrowed. I guess those who are upset, are upset because theories like SUSY seem to be getting shot down left and right. Also, why would the overabundance of photon-photon emissions signify that the higgs is made of composite particles?
Entropy, you’re wrong. We can’t construct the everyday world from QM and relativity, not if you’re referring to our UNDERSTANDING of QM and relativity, as both Sean Carroll and myself were talking about.
You say “It requires no understanding of the wave function’s epistemology to describe a water molecule.” well it does if that’s what you happen to be talking about – the word ‘understanding’ came into the claim of Sean Carroll’s that I was discussing.
It is one thing to know a law of physics, and another thing to understand it. The fact that some physicists nowadays can’t tell the difference is because in some areas we left interpretations behind a few decades ago, and forged on with just the mathematics. We’re now so involved in just the mathematics, that some confuse that with having an interpretation, and with having an understanding.
But some physicists deliberately confuse one with the other, in order to give a false impression to the public, which is irresponsible. It’s similar to the way in which the church used to take power over people, by claiming to know all there was to know. Before that you had the village witchdoctor, he did the same thing. Basically, you say you know everything, and then you have a lot of power. But science doesn’t have to do that, there are many good scientists, who don’t abuse the profession.
Sean, It’s true that you know and understand a great deal about the physics of the universe, but I’ll bet a dollar to a donut you wouldn’t understand my wife.