Scientists close in on 'God particle'

Πηγή: smh
July 3 2012

IN WHAT would be one of the most significant finds in a century, scientists are expected to announce the existence of a new particle tonight that could be the famed Higgs boson.

Scientists have been hunting the elusive boson, which some also call ''the God particle'' because of its importance, for almost 50 years.

It is the last undiscovered particle predicted to exist by the Standard Model of matter and is thought to give all other particles in the universe their mass.

Researchers using two huge detectors at the world's biggest atom smasher, the Large Hadron Collider, will announce the latest results of their searches at a joint scientific seminar in Geneva and Melbourne, where the International Conference on High Energy Physics is being held.

Anonymous members of both teams have told the journal Nature they are excited by their finds. ''Without a doubt, we have a discovery. It is pure elation,'' a scientist using the ATLAS detector said.

A member of the rival CMS detector team said they had also found strong evidence of a new particle.

It is expected, however, that more data will be required to confirm whether it is the Higgs boson predicted by the standard theory or a more exotic form of the boson.

Geoffrey Taylor, of the University of Melbourne, said the results were still confidential and it was important they be presented first at the scientific seminar.

The two teams have been blinded to each other's data, to avoid influencing the independent analyses.

''We're all on tenterhooks. It's a fantastic time,'' Professor Taylor said. ''We know the experiments have now reached a sensitivity so they can say something strong. But we will have to wait and see what the data shows.''

One of the main reasons the Large Hadron Collider was built deep underground near Geneva was to produce particle collisions with a high enough energy to create the fleeting Higgs boson.

It is so short-lived it can only be spotted from an excess of the lighter particles it decays into.

In December, the teams using the ATLAS and CMS detectors both said they had seen tantalising ''hints'' of a Higgs boson.

Researchers declare a discovery only when a result has a statistical significance of five sigma, which means a less than one-in-a-million chance of it being just a fluke. Last year's results had a three sigma confidence rating.

The new results are said to be between 4½ and five sigma, according to the Nature report.

''In practice, you would have to be monstrously sceptical not to be convinced by what we have now,'' one researcher said.