Voyaging where no layperson has gone before, Dani Garavelli tries to unravel the daunting complexities of the Higgs boson

Picture: CERN
Picture: CERN
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THE moment it became clear the elusive Higgs boson had turned up, I put Operation Evade into practice. At first I tried denial. The God particle does not exist, I told myself. It has not been found after a 40-year search; there are no major developments sending ripples of excitement through the world of particle physics.

Annoyingly, rolling footage of excited scientists kept intruding on that fantasy. So I changed tack and tried pleading. Ask someone else to write Scotland on Sunday’s coverage of this moment, I begged. The pandas at Edinburgh Zoo would be better placed than me – whose grasp of physics was tested to its limits during my O Grade exam and whose contemporary exploration of the subject extends no further than watching The Big Bang Theory sitcom – to explain how confirming the existence of this long-posited particle will increase our understanding of the universe.

Eventually, however, I accepted defeat. I could feel the Higgs boson article coming towards me at the speed of a neutrino. I’d better just try to get to grips with its significance. I was going to try to understand this breakthrough, whatever it took. Preferably without getting distracted by the debate over whether Comic Sans, a typeface more redolent of a child’s diary entry than scientific discovery, was an appropriate font in which to release a statement of such moment.

Some of it, of course, I had heard already. You would have had to live in a distant part of another galaxy never to have heard of the Large Hadron Collider, the 17-mile underground tunnel under the Franco-Swiss border where scientists are trying to replicate conditions immediately after the Big Bang by sending particles whizzing towards each other at almost the speed of light. Not least because it cost ¤7.5 billion to build and provoked scare stories that the experiments conducted there would lead the entire planet to be sucked into a black hole.

I knew about Peter Higgs too. He is the Edinburgh academic, who, while walking in the Cairngorms in 1964, came up with the theory that when the universe began all particles were massless. Some gained their mass, he posited, by interacting with a theoretical energy field (later known as the Higgs field) which was created in the moments after the Big Bang and pervades all of space.

For this to be true, Higgs said, the field would have to have a signature particle – the Higgs boson – which would act like glue, binding particles together to form the atoms that make stars, planets and even people. Since the Eighties, the hunt has been on to find the particle, first at Fermilab in Chicago and then at Cern in Geneva. But now it has been discovered – and experts have been talking about it in greater detail – all the clarity I thought I’d gained has evaporated. How exactly does this particle attract mass? If its discovery merely confirms what scientists have thought for more than half a century why is it so significant? And what potential applications does it have in the real world?

That scientists believe the discovery to be of epic importance can be quickly grasped by the rhetoric they have been using. It is as significant as the moon landings, Christopher Columbus finding America or the discovery of DNA we are being told; so significant it is tipped to earn Peter Higgs a Nobel prize.

Last week, the big guns were out in force. Stephen Hawking may have jokingly lamented the loss of $100 (the amount he bet another scientist the particle would never be found) but he managed a broad smile. Meanwhile pop physicist Brian Cox – he of D-Ream fame – could barely contain his excitement as he described the development as “the greatest scientific discovery of my lifetime”.

One explanation for the scale of the celebration was the genuine surprise of everyone involved that the discovery should have come so soon. The LHC accelerates beams of protons up to 99.99999 per cent the speed of light, causing millions of collisions every second. But, it was predicted, only a few Higgs boson particles would be created in every trillion collisions. And since they would be visible for only a fraction of a second before starting to break up, experiments could observe them only by measuring the products of their decay.

Gazing at a chart with a small blip on it as if it were the Holy Grail last week, Joe Incandela, the leader of the CMS experiment – one of the two which claims to have detected the particle – announced scientists had definitely seen something “very, very solid” in the mass region of 125-126 GeV (Gigalectron Volts) – the Higgs boson was predicted to be in the 115 GeV-180 GeV range. “The results are preliminary, but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” Incandala said.

Having analysed a thousand trillion proton collisions, scientists say they are 99.9999 per cent sure what they have found is the predicted Higgs boson. If they are right, then it is the missing piece needed to validate the Standard Model Theory, which describes the basic building blocks of the universe and is to particle physics what the theory of evolution is to biology.

The Standard Model Theory describes 12 fundamental particles governed by four basic forces. Without the Higgs, Professor Brian Cox explains, all the other particles would zoom around without mass and we wouldn’t exist.

To be honest, I’m a bit out of my depth by now. But the nice thing about scientists these days, is that they’re willing to go to extraordinary lengths to try to explain the most esoteric concepts in language the great unwashed will understand. Hence the last 20 years have seen the birth of many analogies – from sharks and whales moving through water to Siberian snowfields – to make the importance of the God particle easier to grasp.

In 1993, Professor David Miller, won a competition after coming up with an political analogy. Imagine, he said, Margaret Thatcher entering a cocktail party full of acolytes, who begin to cluster around her. As she moves, the crowd makes it difficult for her to stop. And if she stops, it makes it harder for her to get moving again.

The beauty of this analogy – in which the acolytes are the Higgs field – is that it can be altered to suit the audience; the central figure can just as easily be George Clooney or Justin Bieber. And by replacing the famous person by a nonentity, who will pass through a room without attracting any such attention, it can also be used to show that some particles – such as light photons – pass through the field without acquiring mass.

Personally, however, I find such personalised analogies distracting. A comic strip devised by PhD Comics entitled Higgs Boson For Dummies is also entertaining, but with its periodic table-style chart of quarks and electrons and taus, it is clearly using the word “dummy” relatively, in the way someone with an IQ of 170 might.

My own eureka-type moment comes courtesy of Edinburgh-based professor of physics Peter Clarke. He explains the Higgs field, using the example of trying to push a balloon (representing a massless particle) through a room while wearing a blindfold. If that room were to be filled with treacle, he says, the balloon would feel heavy. The treacle in this instance is comparable to the Higgs mechanism, permanently giving the object mass.

Professor Clarke has also explained why the discovery of the Higgs boson is so significant. “If we were studying the human body and found a little finger on one hand, after we had already seen five fingers on the other hand, that would be important but not unexpected. It’s not really adding much to what we already know,” he has said. “This is like discovering the heart; without it the entire model of the human body does not work. That is the significance of this particle.”

So far, so illuminating. But a further point of confusion for a layman like me is that even if validated, the Standard Model Theory explains only 4 per cent of the universe. The other 96 per cent of the mass and energy of the cosmos is made up of dark matter and dark energy, about which far less is known.

This being the case, doesn’t the discovery of the Higgs just underline how much we still don’t know? Cox says one of the exciting things about the newly-discovered particle is that it paves the way for further exploration. “We have found a particle that behaves in exactly the way that was predicted in exactly the place we thought it would be found, but there are lots of different ways in which it could be doing its job,” he has said. “The challenge now is first of all to absolutely prove this is the Standard Model particle – there could be more than one, we don’t know yet – and to get into high precision measurements to see if it behaves exactly as expected, or are there subtleties?” If it turns out to be “slightly more exotic” than predicted, it could hold the key to understanding dark matter, he added.

But what of the practical applications? Though the potential impact of the discovery of DNA was perhaps more obvious to the layman then the discovery of the Higgs boson, Cox is confident society will eventually reap the benefits. “The honest answer is I don’t know what this particular piece of knowledge will deliver,” he said. “But history tells us exploring the way the universe works has delivered civilisation. One hundred years ago the cutting edge was the discovery of the electron , the sub-atomic particle. Life now would be unthinkable without our understanding of the sub-atomic world. And then there is the quantum theory of the 20s and 30s – it led to the discovery of the transistor.

“This [the Higgs boson] is at the cutting edge of our understanding right now. But understanding the universe is self-evidently the sensible thing to do because our civilisation is based on it.”

Perhaps for people like me, who will never fully grasp the complex science that lies behind the Theory of Relativity or the Standard Model Theory, it’s enough just to acknowledge that the creation of the Large Hadron Collider and the discovery of the Higgs boson demonstrates what the sharpest human minds are capable of. That and the value of perseverance. Now, that I understand. «