AND ANOTHER THING
When Cap'n Bob and the Prince of Darkness went quark-hunting in a Bubble Chamber
PAUL JOHNSON
do not claim to understand the physics of subatomic particles, but I am interested in their contribution to our language. I like the idea of a quark, an appealing creature which sounds as though it might have been invented by Edward Lear. Officially a quark is defined as 'a point in space of no measurable size', but I suspect it is bigger than that and certainly more significant. I prefer quarks to leptons, sinister things, rather like Marxists posing as New Labour. 'You can 'couple' with a quark and `decou- ple' from it, though the latter produces an Electroweak Reaction — rather a feeble consequence you might think. I feel I could do business with quarks, though not with leptons. The trouble is, most grand unified theories 'tend to bring the quarks and lep- tons together in one big family'. Such a family would include 'bosons'. I don't know what they are but an X-boson is said to be 'very massive'. They encompass photons and gluons and, below them, or possibly inside them, photinos, winos, gluinos, gray- itmos and zinos. Each has a lifetime or a half-life. 'Proton decay' can occur 'often or very rarely', not a helpful statement if you meet a decayed wino on a dark night, espe- cially if it's carrying a Large Electron- Positron Collider, as many do these days.
There are innumerable quarks, and .a good question to ask at physics seminars is 'What Makes a Top Quark?' You see, there are Top and Bottom quarks (rather like les- bians), Up and Down quarks, Charm quarks and Strange quarks. A Strange quark can produce 'cascade baryon' and a positive shower of red, green and blue glu- ons. I'm sorry to bring Cap'n Bob into it here, but there is an explanation called "Maxwell's Electron-Magnetic Theory'. This may not of course have anything to do With Mirror-Pension Maxwell, wearing his baseball cap the wrong way round and wag- gmg his huge bum as he strolls from one gravitino to another. His favourite saying was `Strig theories can produce inconsisten- cies if they include the concept of Super- sYmmetry'. It is a fact that there is a Higgs's Particle, or rather something known as 'the Missing Higgs's Particle', and I expect Maxwell had something to do with that. The matter can be tested in the magnetic field of a Bubble Chamber, which shows how electrons produced from gamma rays Furl up in opposite directions to form infinitely small Catherine wheels of red,
blue and green gluons, and then vanish — a typical Maxwell ploy.
It's not clear if quarks are an oppressed class or employ servants. One physicist has compared them to 'prisoners in a chain gang'. On the other hand, they are kept informed by their personal Messenger Par- ticles. I read: 'The virtual gluons that flit between the quarks within a hard-on are not neutral but carry mixtures of colour and anti-colour.' I am not sure exactly what anti-colour is, but it's something to do with the Turner Prize. The term hard-on is also puzzling. Scrutinising my hurried notes, I fear this may be a mis-transcription for hadron, since I know that Oscar Greenberg and Yoichiru Nambu have done a lot of work on 'the colours of hadrons'. The names of the experts are almost as good as the scientific terms they have coined. Hail Sheldon Glashow, Abdul Salam, Chen Ning Yang and Murrary Gell-Mann! Here's the stuff of poetry! Nor must I forget Gerard 't Hooft and his ringing assertion: `Elec- troweak theory is renormalisable.' Sub- atomic particularists are notable for their °biter dicta, such as the famous lab saying (you can bet your half-life it has a Freudian subtext): 'Scatter me off an electron and I will leave no track.'
Not every quark knows whether it is a particle or an anti-particle or, for that mat- ter, a proton synchroton, subject not only to alpha decay but beta decay too. Strig theory cannot answer this question. Nor can quan- tum chromodynarnics. It puzzled Nils Bohr. It baffled Max Planck. It led to the one recorded joke of Bohr whose sense of humour, as his name suggests, was Nil. When Planck complained that the quark problem was 'terrible', Bohr replied, 'You ought to be able to walk it.' Vork it, how you mm?' The plank, dumb-cluck, walk the plank. Ha! Ha!' Of course Bohr and Planck are old hat now, and have not necessarily worn as well as Laurel and Hardy movies or even W.C. Fields. Atoms were first described by Leucippus and his pupil Dem- ocritus around 500 ac, so the thing is 2,500 years old. But progress speeded up in the last century and it may be my notes are already out of date and that someone has found Higgs's Missing Particle, and even his 'Hidden Symmetry' concealed behind it. Unfortunately our knowledge of sub- atomic particles is not stable. It can be spun. You mean that spin-doctoring now takes place even in the labs? Certainly. And, believe me, a spinner who holds a doctorate from MIT or Imperial College makes Peter Mandelson look an amateur and Alastair Campbell what Democritus would have called a 'a mere hoplite'. Strictly speaking, spin is defined as 'the internal angular momentum that the electronic particle pos- sesses'. But we all know there's more to it than that. In theory 'angular momentum' is 'angular velocity multiplied by mass'. But suppose it's multiplied by anti-mass? There's an old lab saying, 'Things look dif- ferent once you're inside a Bubble Cham- ber.' And you can say that in spades if you're unlucky enough to fall into an Elec- tron-Positron Collider, especially a large one. That happened to Abdul Salam once, and Chen Ning Yang and Murrary Gell- Mann had trouble getting him out. As Shel- don Glashow said to him, 'You were within an anti-second of becoming a virtual gluon.'
The truth is, spinning is going on all the time in the world of competitive physics. There is not only positive spin, negative spin and neutral spin, but also isospin; a desperate device (in my opinion) known as 'extreme subatomic damage control'..Glu- ons are massless and have a spin quantum of one. That means they are difficult to spin. But Professor Yakawa has found a particle with a spin quantum of zero, meaning you can't spin it at all. It is known as the Prescott Particle. As Oscar Green- berg and Yoichiru Nambu have discov- ered, hadrons are of different colours. Also, some hadrons, or hard-ons, are sta- ble, others unstable. Instability makes a difference to the spin too, especially if compounded by anti-colour, and is called the Robinson Effect. That is one reason the list of spin problems is said to be 'as long as an X-boson's arm'. Quarks do not like spinning and try to avoid it by anti- spin configurations. The Up and Down quarks alone come in four different con- figurations, known as uuu, und, udd and ddd. It is all becoming a mite complicated. As Mrs clamp said, 'Rich folks may ride on camels, but it ain't so easy for them to see through a needle's eye.' Some put their faith in Seth Neddermayer's Inter- mediate Particle. Personally I agree with the last sentence of the article I have been quoting: 'It remains to be seen whether Superstring Theory is the much desired theory of everything.'
Previous page
