By Dr Oliver Tearle
Where did the word ‘quark’ come from? And what exactly is a ‘quark’ anyway? The origins of the word ‘quark’ are curious, surprising, and worthy of explanation, so let’s delve into the curious etymology of this well-known, though not always well-understood, scientific term.
For it wasn’t a scientist who came up with the word quark. It was a writer – and one of the most celebrated and acclaimed writers of the twentieth century. So how did a writer come to name the quark?
We need to go back to 1961 to discover the origins of quark … kind of. An American physicist named Murray Gell-Mann developed a way of grouping the various subatomic particles into families. Some were clearly related to each other in the ways they behaved. Others were quite distinct and belonged to a different group altogether.
Some of the earliest subatomic particles to be identified – the proton, neutron, and electron – are well-known even beyond the physics laboratory. A proton has positive charge (+1), a neutron has neutral charge (0), and an electron has negative charge (-1).
But Gell-Mann wanted to understand the particles that were even smaller than these – the particles which made up the particles, as it were.
You see, not all particles have whole charges, i.e., a neat +1 or -1. Some have fractional charges, so +2/3 (two-thirds) or -1/3 (one-third). These fractional particles (with a fractional positive charge) and anti-particles (with a fractional negative charge) together make up the protons and electrons.
So for example, a proton with overall +1 charge might comprise two smaller particles with two-thirds charge and one smaller particle with minus one-third charge. Overall, this would give a ‘balance’ of +1. See?
But what should these smaller subatomic particles with fractional charge be called? One suggestion, made by Gell-Mann’s fellow physicist Richard Feynman, was ‘parton’: suggesting part of ‘particle’ (fittingly), coupled with the -on ending found in the other subatomic particles (proton, neutron, electron). If Feynman’s suggestion had won out, we might well be talking about ‘flavours of partons’ (more on flavours in a moment) today, rather than flavours of quarks!
But Gell-Mann instead suggested quark as the name for these new subatomic particles. In many ways, his suggestion was weirder and carried less etymological logic than Feynman’s, but it was quark that became established as the name. And Gell-Mann found the word in a most unlikely place.
The Irish author James Joyce (1882-1941) is probably best-known for his 1922 novel Ulysses, which tells – in experimental, modernist, stream-of-consciousness style – of one day in the life of a Dublin man named Leopold Bloom. But after Ulysses, Joyce spent the next seventeen years – virtually the rest of his life – working on his next novel, which would be even more experimental than that.
This novel, published in 1939, was Finnegans Wake. In that novel, Gell-Mann found the line, ‘Three quarks for Muster Mark!’
This line is hard to interpret, as with all of Finnegans Wake: a novel rich in puns, wordplay, and obscure allusions. In this case, ‘Three quarks for Muster Mark’ is thought to be a distortion of a man’s cry to a landlord in a pub, ‘Three quarts for Mister Mark’: i.e., ‘Bring me three quarts of beer for Mister Mark’ (a quart is a ‘quarter’ of a gallon, i.e., two pints).
If such an interpretation is sound, it tells us two things. First, the name for one of the most important discoveries in quantum physics comes from a drunken man’s rallying cry for more ale. Second, it raises the question of how we should pronounce quark. Is it quark as in ‘mark’ or quark as in ‘stork’?
Although the rhyme with ‘mark’ is probably more common, if quark came from a pun on ‘quart’ then perhaps a rhyme with ‘stork’ is more justifiable.
Such a pronunciation would also help to distinguish quark (the particle) from the other meanings of the word, which predate Gell-Mann’s co-opting of the word or even Joyce’s coining of it. For quark can also refer to a type of soft German cheese, named after a Germanic term for ‘curds’. This word has been in use in English since at least 1903, so predates the subatomic ‘quark’, and even Joyce’s quark, by decades.
But the cheesy namesake of the physicist’s quark does at least bring us to the issue of ‘flavours’ of quark. You see, quarks come in six flavours: up, down, top, bottom, strange and charm. ‘Flavours’ is just a quirky (or quarky) name for the different characteristics of the quark, i.e., how their mass and charge can differ.