Physicist desperately seeking Susy

Is there a zoo of particles we haven't discovered yet?

It's typical. You spend £2.6bn on a particle accelerator and take 14 years to build it, then people expect the answers to come popping out as soon
as you turn it on. And it is particularly galling when some of the people in question are working on the project.

Particle physicists are up in arms at the moment because a few individuals have had the temerity to suggest that the Large Hadron Collider (LHC) at Cern in Geneva, Switzerland, has already failed to do what we hoped it would. There's a twist in the tale, however: it's about a bet.

There is a fine tradition of making bets on science. Isaac Newton, Stephen Hawking and Richard Feynman have all done it. The Stanford Linear Accelerator even has an open book of wagers on particle physics questions. In August 2004, Ladbrokes was taking bets (at odds of 6/1) that the
LHC would find the Higgs boson by 2010.

The current controversy has been stoked partly by a physicist called Tommaso Dorigo, who has a $1,000 bet that a particle physics theory called supersymmetry will eventually be proved wrong. On the LHC results so far, he is sitting pretty.

On the plus side, people are talking about particle physics. Recently, the House of Commons science and technology select committee has been soliciting ideas about how to make particle physics more engaging to the next generation. As far as I know, no one has suggested getting Ladbrokes involved. Perhaps we are missing a trick.

On the downside, Dorigo's bet risks giving the impression that LHC funding was not money well spent. Dorigo says that if he loses his money on supersymmetry, he won't mind: evidence in favour of the theory - also known, rather endearingly, as "Susy" - would be so momentous as to wipe out any regrets at financial loss.

That's because Susy is essential to modern physics. The goal of physics is to find the simplest explanation for everything and that's what Susy is all about: it contends that all the forces of nature - electromagnetism, gravity and so on - are derived from one "superforce".

I'm sparticle

The theory is straighforward enough: it says that there is a zoo of particles that we have not discovered yet. These supersymmetric particles - "sparticles" - are a kind of mirror world: the electron is partnered by the "selectron", the quark by the "squark", the neutrino by the "sneutrino", and so on.

These sparticles should appear in the LHC as it ramps up the energy of its particle collisions. The simplest versions of Susy say that sparticles should be appearing at energies that the LHC has already reached. Hence the current controversy: with no sparticles in sight, we will, at best, require much uglier, more convoluted versions of Susy.

But there's nothing to say that Susy has to be as simple as possible, so it's too soon to wring our hands. LHC physicists have outlined 14 tests for Susy and Dorigo's confident pronouncements about its death are based on just two of them.

Doing the rest should take about three years, all being well. If Susy hasn't shown its face by then, that is the time to panic. The theory will be in serious trouble, as will the whole edifice of physics. Only Dorigo will be better off.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 14 March 2011 issue of the New Statesman, Who owns the world?