IT HAS eluded scientists for almost five decades and given a Hollywood-style nickname to reflect its lofty status. But time may soon be up for the hard-to-nail Higgs boson - or ''God particle''.
Anticipation is high that, come Wednesday on the eve of a major international conference which will draw more than 800 physicists to Melbourne, one of science's greatest mysteries will be answered.
Described as the last ingredient of the standard model of particle physics, confirming the subatomic particle's existence has been top of the wish list because it is thought to explain why all particles have mass. Understand that and you take a leap forward in understanding how the universe formed and what matter is made of.
Despite obvious obstacles - it can never be seen and currently exists only in theory - little expense has been spared to pin down the Higgs boson. It is the focus of one of the world's biggest scientific experiments - for which the $A9.78 billion Large Hadron Collider in Europe was planned and built over almost 16 years.
''It's esoteric,'' admits Melbourne University's Professor Geoffrey Taylor, who co-ordinates Australia's participation in the collider's ATLAS detector, one of four detectors located around the collider's 27-kilometre ring. ''But we're trying to understand the processes which were occurring at the very beginnings of the universe. It's really exciting, compelling stuff.''
The collider, a giant underground atom-smasher that straddles the Swiss-French border, ceased collecting data this month ahead of the biennial conference. Data analysis was completed yesterday.
The original plan was for that data to be analysed and unveiled at the International Conference on High Energy Physics in Melbourne. But last week the organisation behind the Large Hadron Collider, the European Organisation for Nuclear Research or CERN, announced it would have a ''curtain-raiser'' seminar in Geneva to provide an update on the hunt for Higgs.
The announcement sent bloggers and tweeters into overdrive, speculating that this was going to be the big one. After being denied the news at the previous high energy physics conference in Paris in 2010 when many observers believed it was close, surely this would be it.
The #higgsrumors hashtag quickly began trending on Twitter last Saturday. The attention prompted pleas from scientists to keep a lid on it until the official announcements are made in Geneva by CERN director-general Rolf Heuer and the heads of two of the four detectors.
''Higgs latest results to be announced in Melbourne on July 4th. Let's wait for the answers, rather than speculating,'' tweeted 2011 Nobel laureate and astrophysicist Brian Schmidt on Sunday.
Serious progress has been made at the collider in recent years, which has provided a welcome change after electrical failures caused two false starts in its early life.
Last December the international army of particle physicists working on the mega-project revealed that they had narrowed the energy range in which they were searching for the Higgs boson. The range has since been narrowed further.
''We don't know what we're going to find but we do know that we have reached levels of sensitivity which are higher than what we thought we would,'' says Taylor.
''We know that we have the sensitivity to say something definitive in that region. Exactly what we say will depend on what the data tells us. But it is possible to see a Higgs boson in that space or to exclude it now.''
Armed with more than double the amount of data available before last December's announcement, next week's results are also the product of refined analysis techniques and scientists' improved efficiency in picking out Higgs-like events following collisions.
According to CERN, there was more data delivered from experiments at the Large Hadron Collider between April and June this year than the whole 2011 run. ''That should be enough to see whether the trends we were seeing in the 2011 data are still there,'' says CERN director for research and computing, Sergio Bertolucci. ''It's a very exciting time.''
A dedicated global grid made up of hundreds of thousands of computers has been crunching the data generated from the ATLAS detector alone, including 1000 based in Melbourne. About 6 petabytes - a million gigabytes or 200,000 DVDs - of data from ATLAS has been collected and analysed since December. The competitor experiment being run at the CMS detector, which like ATLAS is a general purpose detector, has generated a similar volume of data.
Having completed the latest round of smashing particles into each other and analysing the debris for clues to Higgs' existence, there is just a matter of days between crunching the data and making the announcement. It's a rapid and rare turnaround for a field that is traditionally so considered and reliant on peer-reviewed publications. The results announced next week will be preliminary and the data will be re-analysed in coming weeks. Taylor says the data from December's announcement was not published in journals until May. ''When things were published, and I think there were in the order of 50 papers, very little changed,'' he says.
Having thousands of scientists working on the Large Hadron Collider - there are 3000 physicists on the ATLAS detector alone from 170 institutions in 40 countries - provided a built-in checking process. ''The hardest thing about getting results out is getting it through the collaboration itself, which consists of 3000 people, all of them highly critical.''
And while hopes are high that there will be an answer on Wednesday, there is no guarantee that it will be the answer to the question so many physicists are asking. It may be that Higgs doesn't exist after all, or that a more exotic version has been found.
''I'm confident that it will be an exciting result whether it's the standard model Higgs or whether the standard model will have to be re-written or indeed if we find something unexpected,'' says Taylor. ''Either of those three solutions is really exciting, so the champagne will be out no matter what we discover.''
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