Q&A

Thu, Jul 5, 2012, 01:00

What is a Higgs boson?It is an elementary particle, much smaller than an atom and something that physicists have been trying to find for decades. There are lots of elementary particles – the bits that go to form atoms that in turn go on to form things. The Higgs is important and special for lots of reasons though.

Why are they looking for it?

It is the last missing piece of a grand theory of how everything interacts, from how electricity and magnetism are linked to why atoms stay so tightly packed together. All the other particles in the theory, known as the Standard Model, have been found. Scientists are anxious to complete their Standard Model as doing so helps to prove the model is accurate.

Why is it in the news now?

Scientists at Cern, Europe’s nuclear research centre on the French/Swiss border reported yesterday that they had found a boson, one they were 99.999 per cent sure must be the Higgs. A few more weeks of analysis may be enough to allow them to confirm that the Higgs exists, but most physicists believe that this is it, they really have the Higgs.

What is the Higgs good for?

It plays a remarkably important role in just about everything from an atom to a galaxy.

Its job is to give mass to the subatomic particles that in turn go on to form things no matter whether they are people or planets.

All things have mass but only because the Higgs is present to give them mass. This is why finding and confirming the Higgs is so important to the Standard Model.

How does it give things mass?

Scientists believe that Higgs bosons were formed immediately after the Big Bang, the explosion that created the universe. The Big Bang kicked out Higgs particles but others too, the ones you need to make things.

The presence of the Higgs bosons caused a field to form. The other particles were able to interact with the Higgs field, gaining mass as a consequence. Once they had mass they were able to interact and behave as we see them doing today.

Why should I be interested in any of this?

Aside from providing you with useful table quiz answers, it is no small thing that the Higgs field allows things to have mass. Without it life could not exist because things like gravity would not work. With no mass, gravity can’t build suns and planets and ultimately people. All the other particles would be floating about unconnected.

Is the discovery of the Higgs boson going to change my life?

Not really. It is not like the discovery of a new drug or some new energy-saving device that will make your life better. But this is fundamental knowledge, a deeper understanding of the universe and the way it works. It is the role of science to try to understand how things work, how things interact. But it is valuable for you to realise that these kinds of discoveries are being made.

How did they find the Higgs?

Cern is the home of the world’s largest atom smasher, the large hadron collider, an enormous machine built over 20 years and costing €4 billion. It is basically an empty tube 27km long that forms a continuous ring. The researchers use massive and powerful magnets to send the centre or nucleus of a hydrogen atom around and around the ring, speeding it up to close to the speed of light.

There are actually two beams of nuclei or protons moving around the ring in opposite directions. They cross these beams causing millions and millions of proton collisions.

The scientists use massive detectors to see what happens to the particles that come out of these collisions, including signs of the Higgs boson.

How do they know it is a Higgs?

Different particles break down in different patterns, emitting an expected collection of yet smaller particles. There are different ways to prove a Higgs was there based on what you see flying out of the collision.

The researchers watch for the tell-tale patterns that can confirm they have a Higgs event. This is where the detectors positioned around the Cern ring come into play.

The detectors can read what is happening during the trillions of collisions that have occurred while the collider is running. This in turn produces masses of data which must be studied in close detail to separate out the events that look like Higgs events.

So is this the end of it all?

Anything but. The people at Cern repeated several times that the discovery of what is likely to be the Higgs is only the beginning. There is much more to do.

Initially they will be looking for final confirmation that this is really the Higgs.

Then the collider is going to reach still higher energies to help explain how the Higgs interacts as it does with other particles.

Higher new energy levels will allow the scientists to learn more about all of the known particles, and maybe there will be surprises too.

Online: irishtimes.com

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