Why bother with that Higgs boson? What’s so great about it? Why did it, last summer, hit the headlines and dominate the cover stories and create traffic jams in the social media world?
And, is there any hope for those of us who do not actually get it? Probably not. So let’s try. Let’s start with the pronunciation of boson. The first syllable, bos, rhymes with gross. The gross boson. Or, you can pronounce it the zzzz way (BOZon) There. I’m starting to feel better.
The standard model of particle physics “describes how elementary particles and a set of forces between them lead to all matter and most higher interactions,” including the stars, the vine maples in my front yard, and the mocha steaming in this yellow mug beside my computer. (The quote comes from a superb primer on the Higgs boson—the December 21, 2012, issue of Science.)
Welcome to the Hall of Particle Physics. Here is reality—our world—at its most elementary. Particles and forces that act on particles. And fields. A field is a region within which any particle is affected by a force.
Fundamental particles. If you divided stuff until it reached its most elementary, most indivisible state, what would you get? Atoms, we used to think. (Atoms remain the indivisible constituents of chemical elements—hydrogen, oxygen, carbon, iron, etc.) But it turned out that atoms are made of subatomic particles—protons and neutrons in the nucleus, electrons spinning around the nucleus within areas called orbitals.
Electrons are fundamental particles. Protons and neutrons are made of quarks, and quarks are fundamental particles. Different types of quarks have been given comely names—up, down, strange, charm, bottom (also called beauty), and top. A proton has two up quarks and a down quark, and these are held together by a massless particle called a gluon.
Yes, some particles have no mass. Mass is the amount of matter in a particle or object. It is not weight. Weight measures the force of gravity being exerted. On the moon you weigh less but you have the same mass.
The most familiar type of massless particle is light. Light arrives in photons, which behave as both wave and particle. If photons had mass, we would be done for, since photons hit us constantly during daylight. A photon is a type of boson. Bosons are involved in the transmission of forces between matter particles. The photon carries the electromagnetic force.
A gluon is another type of boson. Gluons carry the strong force, the one that holds atoms together. Quarks emit and absorb gluons. The gluon is the glue that holds quarks in place, exerting no force until the quarks start pulling apart. In that event, gluons pull them back together as if quarks were dogs on a leash.
Other bosons, the W and Z bosons, carry the weak force. The weak force is involved in radioactivity.
A field is an area domesticated by a force. A gravitational field (to give an example that is familiar but not part of the standard model) is the region within which particles are affected by gravity. (In theory any field should have a particle, but a particle to go with gravity—a graviton—has yet to be found.) An electromagnetic field is the region within which particles are affected by electromagnetism.
In theory, the Higgs field pervades the universe and conveys mass to electrons. Without something to convey mass to electrons we would not have atoms, and without atoms we would not have us. A particle—the Higgs boson—associated with this field should be detectable. Peter Higgs and others proposed the Higgs boson in 1964; the effort to find it has lasted decades and involved thousands of researchers.
The Higgs boson is ultratransitory and not itself detectable, at least not given present technology. But it decays into other particles (such as those beautiful bottom quarks), which are detectable. So, as we know, on July 4, 2012, the likely discovery of the Higgs boson was announced by two teams that had labored to find it at CERN, Europe’s particle-physics laboratory near Geneva. The excitement and even joy at the discovery has to do with the fact that the Higgs boson is “fundamental to understanding our universe.”
Remaining are many mysteries, conundroms, and questions, as any cursory reading of the burst of news following the discovery of the Higgs boson will tell you. But there’s no better time for those of us who find it a bit strange to stick our toe into the waters of particle physics. After all, the universe it describes–now better than ever before–is our own.
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