A self-effacing grandfather who lives in sedate retirement is favourite to win the greatest accolade in science when the secretive Nobel Committee for Physics announces its decision next week.
But the clamour to honour Peter Higgs for the seminal breakthrough he made nearly 50 years ago has created a headache for the committee – which must decide whether to recognise other scientists linked to the subatomic particle or "boson" that bears his name.
The 83-year-old professor lives in Edinburgh having retired from Edinburgh University in 2006. He spends his spare time playing with his grandchildren, reading novels, listening to classical music and walking in the Highlands. He continues to monitor developments in his field by reading the latest physics journals.
Since 1964, when Higgs first proposed a subatomic particle, popularly known as the God particle, that creates a universal force field influencing matter, physicists have tried to find a way of proving its existence, thereby completing the Standard Model of physics – possibly the most elaborate and precise theory in all of science.
This year, researchers working on the Large Hadron Collider (LHC) machine at the European Organisation for Nuclear Research (Cern) in Geneva announced that they had finally found the elusive Higgs, or something fitting its description pretty closely.
Although absolute, conclusive proof is not likely to come for a few more months, almost everyone in the field is convinced that the Higgs boson, or at least one of perhaps several Higgs bosons, has been confirmed. "There is no doubt that we have found a Higgs boson. The theoretical idea is 48 years old and has already been used to underpin other Nobel prizes. The question is who should share the prize?" said Frank Close, emeritus professor of physics at Oxford University.
Although Higgs is the favourite, the Nobel committee can award it to up to three people, each of whom must still be alive at the time of the announcement. The difficulty is that five other living scientists could each present a reasonable case for sharing the top prize in physics. One of them even published his own theory to explain the existence of mass several weeks before the 1964 scientific paper of Higgs.
François Englert of the Free University of Brussels published his theory with colleague Robert Brout, who died last year, on 31 August 1964, seven weeks prior to the seminal paper by Higgs. Englert and Brout deserve to be recognised alongside Higgs, said Chris Llewellyn Smith, who as the former director-general of Cern managed to get the LHC approved and built.
However, with the recent death of Brout there is now a possible vacancy for the third share of the prize, which could go to Tom Kibble, an emeritus professor of physics at Imperial College London, Professor Llewellyn Smith said. Kibble could be the "third man" because of his seminal work published a few weeks after the publication of the Higgs paper, he said.
Another difficulty with awarding this year's physics Nobel to anyone connected with the Higgs boson – including Professor Higgs himself – is the fact that the confirmatory results from Cern came just when the Nobel committee was compiling its shortlist of nominations. The news from Cern in July may have come too late for the Nobel committee, which might prefer to wait before awarding the prize to Higgs, Professor Llewellyn Smith said.
"He's got to be the hot favourite for next year, but who knows?" he said.