Higgs v Hawking: a battle of the heavyweights that has shaken the world of theoretical physics

It began with a dinner in a quiet restaurant, involved an off-the-cuff comment about a famous personality and ended with a very public clash of egos.

This sequence of events may be par for the course in politics but it is rare indeed in the lofty world of particle physics and cosmology – especially when it involves Britain's most famous living scientist.

Yet Stephen Hawking, the Lucasian professor of mathematics at Cambridge University, was accused yesterday of receiving instant credibility because of his celebrity status.

His accuser, a mild- mannered, retired scientist, is not the firebrand you might expect to find squaring up to the man who has been lionised as one of the world's greatest thinkers. Indeed, so modest is Professor Peter Higgs that he refuses in public to call the elementary particle named after him by its real name – the Higgs boson – preferring to give it the more impersonal moniker, the scalar boson.

Professor Hawking, author of the best-selling A Brief History of Time, meanwhile, has appeared in television advertisements and took a cameo role in Star Trek: The Next Generation. His high profile is in stark contrast to Professor Higgs' more prosaic nature.

Colleagues and friends of Professor Higgs were surprised, therefore, to read an article in The Scotsman yesterday in which the eminent particle physicist from Edinburgh University launched what appeared to be a deeply personal attack on Professor Hawking, who is confined to a wheelchair and speaks through a voice synthesiser.

"It is very difficult to engage him [Hawking] in discussion, and so he has got away with pronouncements in a way that other people would not," Professor Higgs is quoted as saying. "His celebrity status gives him instant credibility that others do not have."

The bone of contention between the two men appears to centre on the Higgs boson itself. Professor Higgs predicted the existence of such a sub- atomic particle in the 1960s and scientists have since spent millions trying to find it, using huge atom-smashing machines called particle accelerators.

Professor Hawking, who is known for waging bets with colleagues, put money on particle physicists failing to discover the Higgs with the Large Electron Positron (LEP) particle accelerator at the Cern nuclear laboratory in Geneva.

Much to the disappointment of particle physicists, the LEP finally closed down last year without finding the elusive boson. Professor Hawking may have won his bet, but in his triumph he failed to win many friends among the disgruntled fraternity of particle physicists.

The rivalry between particle physicists and cosmologists may seem odd, given that it is difficult to think of two academic disciplines whose worlds are so different.

Cosmologists such as Professor Hawking work in the ultimate arena of massive objects – stars, galaxies and the universe itself – whereas particle physicists work in the Lilliputian world of sub-atomic particles with names such as quark, lepton and gluon.

One of these particles is the Higgs boson, which is supposed to explain why objects have weight. The American Nobel prize-winner Leon Lederman went as far as to call it the "God particle" because he believed it to be so fundamental to a unified "theory of everything".

But although the two disciplines work at opposite ends of the cosmic scale, they overlap considerably in terms of trying to understand the fundamental forces that bind and repel matter. The centrepiece of modern physics is the Standard Model, the culmination of 100 years of effort by some of the best minds in science. The model reduces the universe's fundamental building blocks to a set of rules basic enough to fit on a T-shirt – cosmologists such as Professor Hawking love encapsulating their thoughts on T-shirts.

The trouble with the Standard Model, however, is that it predicts the existence of the Higgs boson because without it everything would be weightless. There would be no stars, planets or people because all matter would be flying through space at the speed of light.

Finding the Higgs boson, therefore, was seen as one of the greatest contributions that particle physics could make to understanding the universe. Unfortunately, after spending many years and a small fortune, the LEP scientists in Geneva failed to prove its existence.

Whether Professor Higgs himself is rattled by the failure is anyone's guess – he was unavailable yesterday – but his comments over a glass or two of wine at a restaurant just off Edinburgh's Royal Mile suggest he might be.

The dinner was arranged (and paid for) by the Particle Physics and Astronomy Research Council to celebrate a play at the Edinburgh Festival based on the work of Paul Dirac, an eminent English physicist who won a Nobel prize in 1933 for his work on relativity and quantum mechanics.

Professor Higgs was speaking for many when he suggested Professor Hawking had hogged the limelight. Although particle physicists may have cause to feel aggrieved by Hawking's apparent arrogance, the feeling is in fact shared in private by many cosmologists, who get exasperated by the media's constant reference to him as the greatest scientist since Einstein or Newton.

"Paul Dirac made a far bigger contribution to physics than Hawking yet the public has never heard of him," said one scientist. But it is a criticism that dare not speak its name. "To criticise Hawking is a bit like criticising Princess Diana – you just don't do it in public," said another cosmologist.

As the wine flowed in the Edinburgh restaurant, so presumably did the conversation. Professor Higgs only said what many other scientists say about Professor Hawking in private, but its prominence in a newspaper article makes it appear a planned, personal attack, which is clearly not what Professor Higgs intended.

"To be honest, I was surprised to see Higgs' comments. It's not his style at all. Physics is full of vindictive, nasty people but Higgs is not one of them," one scientist said.

As for Professor Hawking, there were no signs yesterday of his famous sense of humour. "I am surprised by the depth of feeling in Higgs' remarks. I would hope one could discuss scientific issues without personal attacks," he told The Independent.

Meanwhile, scientists are continuing their quest to find the holy grail of physics. In five years, a far more powerful machine at Cern called the Large Hadron Collider is due to begin the search afresh. The higher energy levels of this new machine cannot fail to find the Higgs, say the optimists. It will be a final vindication of the many millions of pounds spent on some of the most expensive experiments ever undertaken.

A BRIEF HISTORY OF SCIENTISTS AT LOGGERHEADS

Peter Higgs, Professor (Emeritus) of theoretical physics at Edinburgh University

Age: 60

Educated: Cotham Grammar School, Bristol, and King's College London.

Claim to fame: Predicted the Higgs bosun particle in the Sixties, further work in classical and quantum fields of research.

Awards: Hughes Medal (Royal Society) 1981, Paul Dirac Medal 1997.

Communications: Mainly by letter, does not have e-mail or television.

Quietly spoken.

Higgs on Hawking: "He has got away with pronouncements in a way that other people would not. His celebrity status gives him instant credibility that others do not have."

Stephen Hawking, Lucasian professor of mathematics at Cambridge University

Age: 60

Education: St Alban's School and University College, Oxford

Claim to fame: Author of A Brief History of Time, a best-selling book about the beginning and end of the universe. Predicted "Hawking Radiation" emanating from black holes.

Awards: CBE 1982, Companion of Honour 1989. Hughes Medal (Royal Society) 1976, Paul Dirac Medal 1987.

Communications: Paralysis from motor neurone disease forces him to talk through a voice synthesiser connected to a computer.

Hawking on Higgs: "I am surprised by the depth of feeling in his remarks. I would hope one could discuss scientific issues without personal remarks."