Monday, August 16, 1999 Published at 14:29 GMT 15:29 UK
Scientists see Susy
By BBC News Online Science Editor Dr David Whitehouse
Scientists call it Susy, a theory of matter called supersymmetry that may say something deep and profound about the Universe. The first experimental evidence for it may have been obtained by German and American scientists.
Their observations at a particle accelerator in Germany suggest we may be on the verge of a new understanding about the way the Universe is made.
Unravelling the nature of matter has been one of the great successes of modern science. Atoms are made of three types of particles: electrons, protons and neutrons. Light is made of particles called photons.
Our world is made of these along with a few others. But behind them is a remarkable pattern of other particles.
By smashing together sub-atomic particles in giant accelerators, scientists can create minute and fleeting concentrations of energy out of which other families of particles form. Some of them have not been around since the Universe cooled after the Big Bang some 15 billion years ago.
From such experiments, it is known that protons and neutrons are made of smaller particles called quarks while the electron is a truly fundamental particle that is not made of anything smaller.
From this work, a description of nature's particles called the Standard Model has emerged. Among other things, it states that particles can be either bosons or fermions. But the so-called standard model does not explain everything and scientists have been looking for a more powerful one. One of the candidates is called supersymmetry.
Supersymmetry is an idea that has been around for decades. It states that every boson has an associated fermion and vice-versa. So a quark, which is a fermion, has a supersymmetric partner called a squark which is a boson. Likewise a photon, which is a boson, is teamed up with the photino, a fermion.
Unfortunately, none of the proposed supersymmetric particles have ever been detected. Scientists say this is because current particle accelerators are just not powerful enough.
But now, according to PhysicsWeb, some evidence that supersymmetry is real may have emerged from a study of gold and platinum atoms.
Teams from the Ludwig-Maximilians University in Munich and the University of Kentucky in the United States have used the Tandem accelerator in Munich to bombard gold atoms with sub-atomic particles. The results of the interactions between the targets and the projectiles, they say, can only be explained by supersymmetry.
"The fact that they claim to have found a realisation of supersymmetry in nature is exciting," said Dr Herbi Dreiner of the Rutherford Appleton Laboratory in England.
It is hoped that the powerful LHC particle accelerator at the Cern nuclear research institute in Switzerland will uncover definite evidence for supersymmetry when it comes online in 2005.