Nobody has ever seen a mysterious, sub-atomic fragment that permeates the atmosphere and explains how everything is the way it is.
They call it the ”God particle”. Some say it doesn’t exist but, in the ultimate leap of faith, physicists across the world are preparing to build one of the most ambitious and expensive science experiments the world has ever seen to try to find it.
At a summit meeting in Beijing last month, 12 experts from countries including Britain, Japan, the United States and Germany announced they have agreed on a blueprint for the new experiment — a gigantic, atom-smashing machine called the international linear collider. Now they must convince their respective governments to meet the anticipated £3-billion (about R33-billion) price tag.
Buried underground away from vibrations on the surface, the collider would accelerate particles from opposite ends of a 32km tunnel at near-light speeds and smash them into each other head-on. One stream of particles would be electrons, the other would be positrons — their anti-matter partner.
The scientists hope the resulting cataclysmic explosion of heat, light and radiation will recreate the conditions found in the first few billionths of a second after the Big Bang. And when that happens, they hope the ”God particle”, otherwise known as the Higgs boson, will show itself.
Ian Halliday, CEO of Britain’s Particle Physics and Astronomy Research Council, said: ”This is an extremely significant milestone. We now have a clear and defined route for the future that will enable the world’s particle physics community to concentrate resources and unite efforts behind the design.”
Scientists have learned the hard way in recent years that such mega-projects are beyond the reach of individual countries. The US attempted to build its own linear collider in Texas in the early 1990s but the project collapsed amid spiralling costs, leaving it with a £1-billion bill and only a hole in the ground to show for it. If it gets built, the new machine could open the door to a shadowy new domain of physics.
”The international linear collider will take our science into completely new areas,” said Brian Foster at Oxford University. ”It will hopefully reveal new and exciting physics, addressing the 21st-century agenda of compelling questions about dark matter and dark energy, the existence of extra dimensions and the fundamental nature of matter, energy, space and time.”
Key to these discoveries is the Higgs boson particle, which scientists have been searching for since British physicist Peter Higgs proposed it in the 1960s. Physicists want to find it because such a particle would plug a hole in a theory that is both their greatest triumph and their biggest headache.
Just as chemists group the different elements according to their similarities in the periodic table, so physicists use something called the standard model to explain how various subatomic particles interact to make the universe tick. ”Go back 40 years and we were finding particles but we had no idea how they fitted together. We were discovering pieces of a jigsaw but we didn’t have the picture on the front of the box,” said George Kalmus at the Rutherford Appleton laboratory in Oxfordshire. ”We now have a pretty good picture on the front of the box and that picture is called the standard model.”
But the standard model is now starting to show its age, and as physicists devise bigger and better experiments to test its theoretical predictions, they are coming across more and more anomalies. Chief among these is the discovery that even the tiniest, most fleeting particles have some mass — the standard model assumes they don’t.
The Higgs particle offers physicists a way out: they think it somehow interacts with all other forms of matter to give them their mass or, in other words, to make them weigh anything. The idea is so appealing that they have already spent billions of pounds on a succession of more powerful accelerators to hunt it down.
”We keep on looking for the Higgs boson and we keep on not finding it, but we now have an indication of where it is,” said Kalmus. He said existing accelerator machines, built in the shape of rings, just cannot get the particles travelling fast enough or to collide with enough force to reach the energy levels where the Higgs particle is believed to exist.
Another accelerator, the large hadron collider, is already under construction at the Cern laboratory under the Swiss Alps and is due to be switched on in 2007. It could have the potential to find the Higgs particle but will tell physicists little about its interactions.
Kalmus says studying the particle in more detail is crucial. ”The world is running out of easily developed energy sources. If we can learn more about how energy and mass are related in this strange way, who knows what effect that might have?” — Â