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article imageSearching for the Theoretical Particle, the Higgs Boson

By Julian Worker     Mar 16, 2009 in Science
What gave the universe mass - well it's postulated that the Higgs Boson did, yet it's never been seen and may only exist for less than a second. Billions have been spent on trying to find this particle, but the possibility remains that it doesn't exist.
It’s postulated that without the Higgs Boson, or God particle, the universe wouldn't exist because nothing would have any mass -- not you, not the Earth, not the stars you see in the night sky. A lot of money has been spent to find this particle and its discovery would be a major leap forward for science.
Physicists today are searching even deeper to find out more about Higgs Boson.
In the 1960s the British physicist Peter Higgs came up with a theory, which hypothesizes that a web, referred to as the Higgs field, fills the universe. This web is full of Higgs Bosons that cling to all particles passing through the web giving them mass (apart from the photon which doesn’t have any mass). This sticking effect is called the Higgs mechanism and occurred just after the Big Bang at the beginning of the universe.
The problem is that no one has ever seen a Higgs Boson. Yet. There is great anticipation that this unseen particle could soon be found ending over 10 years of trying.
You might have thought that it would be a fairly simple to find one – break up a particle, any particle such as a quark or lepton, and surely inside will be found a Higgs Boson, like a pearl inside an oyster. Not that simple I’m afraid.
The first problem that scientists face is accelerating particles to very high speeds – it’s calculated that researchers must smash other particles together at 99.99% of the speed of light. If the energy produced from the resulting crash is sufficient then it will be converted into particles and the Higgs Boson might be amongst them. The next problem facing scientists is that the Higgs Boson will only exist for the tiniest fraction of a second before decaying into other particles. During its brief existence the boson will have a certain mass which researchers will have to try and detect.
The only places that can realistically find the Higgs Boson are called particle accelerators. When the search started there were two main protagonists the Large Electron Positron Collider (LEP) at CERN (Conseil Européen pour la Recherche Nucléaire - European Council for Nuclear Research) in Geneva and the Tevatron at the Fermilab in Illinois.
The Tevatron accelerates protons and antiprotons in a 3.90 mile ring to energies up to 1 Tera electron Volt. It was completed in 1983 at an initial cost of $120 million and was upgraded between 1994 and 1999 at a further cost of $290 million - a lot of money to try and find something that might not exist. However, this price was dwarfed by the cost of the Large Hadron Collider (LHC) at CERN in Geneva. When you hear its specification you will probably understand why.
The Large Hadron Collider superseded the LEP, which was taken out of service in 2000. It is the largest machine in the world with a circumference of nearly 27 kilometres. The Large Hadron Collider contains 9300 magnets, which when fully operational are pre-cooled to -193°C using liquid nitrogen. The near vacuum that contains the magnets is then filled with nearly 60 tonnes of liquid helium to bring the temperature of the magnets down to -271°C, making the LHC the coldest place in the universe. Then, trillions of protons race around the LHC over 11,000 times per second in opposite directions smashing into each other with a force of 14 Tera electron Volts. 600 million collisions take place every second. The smashed particles generate temperatures that are more than 100 000 times hotter than the Sun. To detect the Higgs Boson, the Large Hadron Collider’s detectors can precisely measure the existence of a particle to a few billionths of a second and its location to millionths of a metre.
All this specification cost around 5 billion euros but there have been problems. In September 2008, a faulty electrical connection between two magnets caused an arc, which compromised the liquid-helium containment. The surrounding vacuum layer was flooded with sufficient force to break 10-ton magnets from their mountings, damage that means the LHC might not be operational until September 2009.
While the LHC is broken the Tevatron is making comparatively rapid progress in its search for the Higgs Boson. By controlling the speed of the collisions, researchers are able to seek out the Higgs Boson by looking for particles of a certain weight, measured in Giga electron Volts (GeV), the equivalent of 1/6000 billion billion grams.
The tests conducted by the LEP until 2000 and recent Tevatron research has narrowed down the weight of the Higgs Boson so that scientists now believe the particle must weigh somewhere between either 114GeV to 159GeV or 171GeV to 185GeV.
To the untrained mind though, even if the Higgs Boson is found, the obvious question is this – the Higgs Boson has a certain mass which when attached to other particles gives them mass, where previously they had none. So, if these particles didn’t have any mass prior to being attached to the Higgs Boson, and all particles were created by the Big Bang, then where did the Higgs Boson get its mass from? Are there other even minuter particles that gave mass to the Higgs Boson? Also, at the dawn of the universe why didn’t the Higgs Bosons attach itself to photons, particles of light?
The Tevatron is closing in on the Higgs Boson and it would be ironic indeed if this accelerator were to find the God particle before the purpose built Large Hadron Collider, showing that spending vast amounts of money is no guarantee of success.
If the Higgs Boson isn't found then scientists will have to find another theory to try and explain why the universe has mass. Watch this space.
More about Higgs boson, Large hadron collider, Tevatron, Particle collider, God particle
 
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