By Ben Hirschler
LONDON (Reuters) - Two scientists who predicted the existence of the Higgs boson - the mysterious particle that explains why elementary matter has mass - are Thomson Reuters' top tips to win this year's Nobel prize in physics.
Recognition for a discovery that made headlines worldwide will come as no surprise, but deciding who deserves the glory is a tricky matter for the prize committee, which will announce its winner or winners on October 8.
The will of Alfred Nobel limits the prize to a maximum of three people. Yet six scientists published relevant papers in 1964, and thousands more have worked to detect the Higgs at the CERN research centre's giant particle-smasher near Geneva.
The consensus is that the award will go to the theoretical physicists whose work has finally been vindicated - and, as Belgium's Robert Brout died in 2011, there are now five contenders. The prize cannot be given posthumously.
Of these, the two likely winners are Britain's Peter Higgs - after whom the particle was named - and Brout's colleague and countryman Francois Englert, according to Thomson Reuters' Nobel prediction expert David Pendlebury.
His predictions are based on how often a scientist's published work is cited by other researchers, and his system has accurately forecast 27 Nobel prize winners since 2002.
Pendlebury believes Higgs, 84, and Englert, 80, are the logical winners this time. Although Brout and Englert were first to publish in 1964, Higgs was second and he was also the first person to explicitly predict the existence of a new particle.
Similar proposals from American researchers Carl Hagen and Gerald Guralnik and Britain's Tom Kibble appeared shortly after, but their papers have garnered fewer citations over the years.
There was speculation of a Nobel prize for the Higgs discovery last year, after detection of a boson at CERN in July 2012. But that preliminary data needed to be confirmed, which only happened earlier this year.
"It seems to me that with the confirmation in March of the experimental results at CERN, it is not difficult to make a strong wager that the discovery will be honoured this year," Pendlebury said.
Half a century may seem a long time to wait for a Nobel prize but, as the experimental evidence is only just in, an award next month would actually be speedy by Nobel standards.
The sense of urgency reflects the importance of the finding - the Higgs boson is the last piece of the Standard Model that describes the fundamental make-up of the universe - but also the fact that both Higgs and Englert are now in their 80s.
Other Nobel prizes will be awarded next month for medicine, chemistry and economics, as well as for literature and peace.
Notable Thomson Reuters nominees in the economics arena include Sam Peltzman and Richard Posner of the University of Chicago for their research on theories of regulation.
In medicine, those tipped include Adrian Bird, Howard Cedar and Aharon Razin, from Britain and Israel, for work on a process known as DNA methylation, which helps determine how and when genes in the body are switched on.
Among potential chemistry winners are U.S. scientists M.G. Finn, Valery Fokin and Barry Sharpless for developing so-called "click chemistry", which has applications in diagnostics and in making surface coatings with unusual properties.
Pendlebury's citation-based system predicts outstanding researchers whose work could earn them a Nobel prize either this year or in the future.
(Editing by Robin Pomeroy)