There was a time when discovering a new particle would win you the
Nobel prize - these days you get a $50 gift voucher and told to stop
causing trouble. The Greeks figured that the smallest possible unit
was the atom - named for their word for 'uncuttable'. This got cut up
into a nucleus and orbiting electrons, then we smashed the nucleus up
into nucleons (protons and neutrons), the electron into leptons, and
just because there weren't quite enough different colours on the
"Sub-atomic particles chart" yet we figured out how to break the
nucleons and other hadrons into quarks.
So it was combination of excitement and a muttered sigh of "again?"
that greeted the predictions of researchers of Luleå University of
Sweden in 2007. Fredrik Sandin and Johan Hansson support the idea that quarks
themselves (previous holders of "that's it, these are the smallest
pieces for real this time" award) are in fact made up of smaller preon
particles. Preon models have been popular as early as the 1980s, after
which they lost ground against the scientifically-sexier superstring
suppositions. Twenty years later and with no pesky 'validation' in
sight, it seems that people are once again interested in proving the
And what proofs they've postulated. Normally a scientist designing an
experiment to detect a tiny sub-sub-atomic structure finds themselves
saying thing like "I think there's this utterly insanely tiny thing
that's never been directly observed in any form, so to prove it I'd
like you to hollow out a mountain for me and fill it with carefully
prepared chemicals". Luckily for scientists swimming against the
string-tide, the proof of their theory wouldn't be quite so costly.
They postulate that isolated clumps of preon matter created during the
Big Bang may have remained stable, rather than following the
preon-quark-hadron-atom-molecule-solid-iphone(or whatever) condensation
that most of the material did.
These hyper-dense chunks of primordial preons would still be shooting
about the cosmos creating effects we could easily observe. These
effects include bending light, creating gravity waves and drilling
lines of seismic shocks through the Earth's crust - so if you can
detect those, you've either foundpreons or are being attacked by the
X-Men. More importantly such seismic signatures could conceivably be
detected in the wealth of seismic data already being recorded worldwide
- and the gravity waves would be of a frequency detectable by table-top
devices rather than the "Bond Villain Lair" scale such equipment
Observation is the only route available to the enthusiastic particle
master ("gotta detect 'em all!") While other sub-hadron units can be
briefly observed with a few miles of accelerator and enough power to
light up a city - don't try this at home - the only way to
produce preons would be to recreate the conditions of the Big Bang.
Nine out of ten Mad Scientists agree that while that would be the most
awesome experiment ever, the only people who'd get useful data out of
it would be whoever evolved to sentience in the newly created universe. The team believed preon nuggets could have been created in the early
moments of the universe and lingered as a form of dark matter that
primarily interacts with normal matter though gravity.
Fredrik and Johan have already worked out a system whereby a trio of
preons could combine to construct all the quarks already observed. The
math is ready, the idea is interesting, and all they're missing is some
experimental verification. Just like all the other theories we have in
that field - but with verifiable tests ready to go, even being proved
wrong would be a useful result for everyone.
Posted by Luke McKinney
Splitting the quark
How preons make quarks (WARNING: Heavy science ahead)