Higgs boson

A group of scientists working at CERN's Particles Physics Research Center near Geneva will present the latest research into the elusive Higgs boson particle at a conference on Wednesday. Just two days ahead of CERN's announcement, US physicists at the Fermi National Accelerator Lab outside Chicago claimed to have found hints of the Higgs boson. But they admitted that their evidence fell short of the scientific threshold for proof of discovery and that they too were waiting for the latest European data.

The Higgs boson is a hypothetical elementary particle that is thought to have been around during the Big Bang. It said to have helped create planets, stars and galaxies out of the debris. If found it could help us understand more about the fundamental laws of Nature. The scientists at CERN have been trying to find evidence of its existence in experiments with the Large Hadron Collider, the world's biggest particle accelerator. DW spoke to CERN's James Gillies.

DW: What is it about the Higgs boson? Why is it so important?

James Gilles: The Higgs boson is a very important particle in our understating of the universe and what it is made of. It was proposed in 1964 to solve an important problem in theoretical physics back then. It is part of a mechanism that endows fundamental particles with mass. So it is a very important principle for particle physics.

The reason why there is so much excitement about it is that it's an idea that has been around for a very, very long time. And we're now in a position with the Large Hadron Collider experiments to be able to say whether or not this particle or mechanism exists, or whether we need to rethink our understanding of nature at the fundamental level. So there is a huge deal of anticipation about what we're going to be saying on Wednesday.

This takes us back to the beginning of our existence from a scientific point of view, doesn't it? The Higgs Boson is thought to have existed during the Big Bang.

Absolutely, the field associated with the Higgs Boson permeates space and always has. And it's through their interactions with this field that particles acquire the masses that they have. It's very important. If particles had different masses by significant measure, then things like us wouldn't be able to exist. So understanding it is a very important thing for science.

Is it just about the understanding? There are a lot of people at the moment asking whether we should be spending so much money on things like the Large Hadron Collider - at a time like this, just for the sake of understanding. What are the practical benefits for us?

The practical benefits are huge, actually. Let's go back to the budget first of all. CERN's annual budget - and we built the Large Hadron Collider out of this budget in about four years - is comparable to that of single, large university. So, we are, if you like, one very focused, large university in the European and global research landscapes these days. What happens is that a lot of very smart and motivated people come here to address deep questions about the nature of the universe. And when they find technological problems, they have a tendency to solve them.

The best known example of a technology that came from CERN is the World Wide Web. Somebody once calculated that the benefit that that's had for the world economy would have paid for all the fundamental research that has ever been done many times over. So, the benefits are definitely there. But it goes much beyond the Web. There are many applications in medicine for both diagnostics and in therapy. A lot of IT companies come here to stress test new products. Technology that is now being developed for the Large Hadron Collider is being deployed in solar energy collection, and the list goes on. There is a lot technology that comes out of here as well as the basic research.

And I suppose that the flip side of this, as you've pointed out, is that a lot of scientists come to CERN from around the world. That would make it some kind of unifying force in Europe - which is something that Europe needs right now, as well as cash.

Absolutely. If you look back at the origins of CERN, in fact, that was part of our mandate back in the 1950s. CERN was established because science was seen in the aftermath after two world wars as a politically neutral activity and something that could unite the countries of Europe. So, it's actually there in our DNA, if you like, that the founding convention of CERN says that we will provide a place for the nations of Europe to collaborate peacefully together.

We can't yet talk specifically about what is going to be announced on Wednesday. But perhaps you could talk us through some of the technological developments since December when we heard there were some "tantalizing glimpses" of the Higgs boson.

What's happened since then is that the LHC has been working extraordinarily well. So, when the experiment stopped taking data two weeks ago in preparation for the year's big physics conference, which starts in Melbourne on Wednesday, they had recorded more data so far this year than they had recorded in the whole of last year. That in itself led to a great expectation that either those signals that appeared to be in the data from 2011 would be much, much stronger by the time we get to now, or will have shown themselves to be a statistical fluctuation and gone away. So, that's what's at stake. A lot more data has been analyzed and there is a huge anticipation that we may soon finally know whether the Higgs particle exists or not.

So, you really want to find out whether you saw it or you just thought you saw it, right?

Exactly. The process of discovery in particle physics is a statistical one. What happens when we bang these little pieces of matter, protons, together is they will sometimes create a new particle, which may be the Higgs boson, which will then itself decay, leaving a characteristic pattern in the particle detector.

Now, the problem is that there are lots of other processes that can leave the same characteristic patterns in the detector. So, what you have to do is count up all the proton collisions that give you that pattern, compare the number you get to what you would expect to get from the physics you already know about, and if you get an excess building up, then you can say you have something new happening. But you need that excess to be statistically significant before you can say it's a discovery because it's a bit like if you flip a coin, you might get a run of heads or tails. And it doesn't always mean that coin is always going to come up heads or tails. It's just a statistical process. And the sort of gold standard for discovery in physics is that the probability of the excess that you see being due to a statistical fluctuation has to be way less than one in a million. So, that's what we're all waiting for.

Interview: Zulfikar Abbany
Editor: Michael Lawton