Search for the Big Bang… but Large Hadron Collider is not large enough

WHEN it was first unveiled, the Large Hadron Collider was heralded as the instrument that would produce a "tiny bang" and reveal the opening moments of the Universe.

But the scientists behind the device revealed yesterday that they now want to delve deeper into the secrets of the Big Bang by creating an even bigger device.

Instead of whirling particles around in vast rings and slamming them into each other, as they are currently doing with the LHC at Cern, a particle physics laboratory outside Geneva, and the smaller Tevatron at Fermilab near Chicago, scientists want a next-generation machine that will shoot them straight along a 31-mile tunnel called the International Linear Collider (ILC).

The most prominent theory of how the Universe works predicts the existence of a Higgs particle that gives matter its mass. If discovered, it could pave the way towards a unification of the theories of quantum and general relativity.

Particle physicists, who gathered in Paris yesterday for the most important conference in their field, say a linear atom blaster is needed to complement what existing colliders are telling scientists about the Universe, inching them closer to understanding the origins of the Universe.

Though the plans were presented to the French president, Nicolas Sarkozy, the scientists are reaching out to China, India and Russia to help fund the next 8.5 billion step of the project.

The new machine would be a successor to the 7bn LHC, which was launched with great fanfare in September 2008, but days later was sidetracked by overheating that set off a chain of problems.

Cern had to undertake a 26 million programme of repairs and improvements before restarting the machine last November. Since then, the collider has reported a series of successes.

Named the Higgs boson, the unseen particle is known as the "God Particle" because, if it is proved to exist, it will support the Big Bang theory.

Barry Barish, a professor at the California Institute of Technology and director of the proposed collider, said of the new project: "If we are going to build an ambitious machine, then it's got to be a global machine".

According to Guy Wormser, a leading particle physicist and one of the conference organiser, they hoped the machine could be turned on in 2020 or 2025. "(With the LHC] we made a machine which allowed us to make a big leap in understanding, a sort of enlightener, and now we study and detail things, and that's the linear collider. It's the future of our discipline."

Depending on who wants to host it - and how much they are willing to pay - the ILC could potentially be built anywhere in the world. Instead of crashing protons together, the new collider will accelerate electrons and positrons, their antimatter equivalent, producing the elusive Higgs Boson Particle to allow closer scrutiny of its properties and potential other particles.

The difference between the LHC and ILC in the degree of accuracy needed in executing collisions has been likened to the difference between firing knitting needles at each other from either side of the Atlantic and trying to make them hit each other, then repeating the experiment using sewing needles.

While electrons and positron collisions are simpler and more accurate to measure, smashing protons was physically easier, as Tony Doyle, professor of physics and group leader of the experimental particle physics group at the University of Glasgow, who is involved in both of the current collider experiments, explained: "Protons, when they circulate in the ring of the LHC, they don't radiate something called synchrotron radiation, but electrons and positrons would, and you'd lose huge amounts of energy. So you have to go to a linear collider, which is a different type of technology, [to make the experiment work]."

He said that if they can examine Higgs boson particle and how it behaves, it could give them the ability to look indirectly for the presence and effect of invisible "virtual particles".

This would allow scientists to look even further back in time, he said, giving them a glimpse of what was happening in the universe "a trillionth of a second after the Big Bang".

Though the purpose of the technology used in developing the colliders is to examine particles, it has gone on to have a fundamental impact on the world.

The World Wide Web was invented by physicists to exchange large amounts of data relating to experiments, and its successor, the Grid, is under development to allow even larger amounts of information to be stored online securely.

The mechanical technology involved in building the colliders has also had medical applications, particularly in developing medical scanners.


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