A quick review of the unusual history of quarks

Image: Large Hadron Collider at CERN. Text: QUARKS--Tiny particles that comprise protons and neutrons. Learn the secret of this unusual word.

Today is Wednesday, so it’s time for our regular feature What is that? Here’s today’s term:

Quark–a tiny particle found in protons and neutrons

A quark is a tiny particle that can be found in any atom. Protons and neutrons, which make up the nucleus of an atom, are made of quarks.

[Read more about atoms and how they were once thought to be the smallest objects in the universe.]

What are the six “flavors” of quarks?

There are 6 types of quarks: up quarks, down quarks, top quarks, bottom quarks, strange quarks, and charm quarks. Some physicists also used to call top quark “truth” and the bottom quark “beauty” but that has apparently fallen out of style, which seems a shame. I like the whimsical names of strange, charm, truth and beauty.

Physicists refer to the different types of quarks as “flavors.” Maybe some of those physicists grew up working in an ice cream shop. (When I use “flavor” to describe something, I’m usually referring to the particular feel or mood I get when I’m reading a particular book.)

As I understand it, the names of the “flavors” don’t really mean anything. They are just tags that physicists placed on different types of quarks to tell them apart. I don’t mean that physicists literally put tags on quarks. Quarks are far too small for that. They are so small that even scientists can’t see them with microscopes. In fact, for decades, physicists just theorized that quarks existed.

Photo of the Globe of Science and Innovation at CERN headquarters.
Here at CERN headquarters near Geneva, physicists use particle accelerators to study subatomic particles like quarks. Photo by Faith Tucker.

In 1964, physicists Murray Gell-Mann and George Zweig, working separately and coming to their own conclusions, proposed the existence of quarks. At the time, they were just describing neutrons, protons, and other rarer particles made of quarks. Back then, there was not much evidence that quarks actually existed.

Cover of The Quark and the Jaguar: Adventures in the Simple and the Complex by Murray Gell-Mann
The Quark and the Jaguar: Adventures in the Simple and the Complex by Murray Gell-Mann

It took until 1968 for an experiment at the Stanford Linear Accelerator Center to provide some real evidence of quarks. And it took until 1995 for physicists to discover real-world evidence of the final quark flavor, the top quark.

The Quark has a literary heritage

Where did the name “quark” come from?

Physicists suggested different names for these tiny particles. It was Gell-Mann’s name–“quark”–that caught on. When thinking up a name, he first decided on the sound he wanted–“kwork.” Later, he ran across the word “quark” in Finnegans Wake by James Joyce and chose that spelling.

I’ve heard the word originally was a German word for curd cheese, and I’ve also read that it can mean “rubbish.” The use in Finnegans Wake might mean curd cheese, or it might mean something entirely different, like a cheer (or “croak”) made at a drinking establishment (a bar) or just a sound a bird might make.

Here’s the quote from Finnegans Wake:

Three quarks for Muster Mark!

Sure he has not got much of a bark

And sure any he has it’s all beside the mark.

Finnegans Wake by James Joyce

I find the source of the word and its original meaning to be as mysterious as the particle itself.

Discover and name your own particle!

Imagine you are a physicist. You discover an unknown particle!

  • What do you name it?
  • Why do you choose that name?
  • What does the particle do?

Please post your comments below.

Be stellar!

Matthew Cross

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