By Robert Evans
GENEVA (Reuters) - With the Higgs boson in the bag, the head of the CERN research center urged scientists on Tuesday to push on to unveil the "dark universe" - the hidden stuff that makes up 95 per cent of the cosmos and is still a mystery to earthbound researchers.
Rolf Heuer spoke after the Nobel physics prize went to Briton Peter Higgs and Belgian Francois Englert for predicting the existence of the Higgs boson particle, which explains how fundamental matter got the mass to form stars and planets.
"We have now completed the Standard Model," Heuer told reporters, referring to the portrait of the known universe drafted in the 1980s.
"It is high time for us to go on to the dark universe," added the director general of the world's main institution focusing on the basic particles of nature, based near Geneva.
The Higgs boson and its associated force field were among the last major building blocks of that model of how the cosmos works.
Their existence was confirmed, after three decades, when the particle was seen last year in CERN's underground particle smasher, the giant Large Hadron Collider (LHC).
The LHC, now in the middle of a two-year refit and upgrade, is due to resume operations in early 2015 with its power doubled.
"That will open promising territory into new physics," Heuer's deputy Sergio Bertolucci said. New physics is the term used by scientists for the realms beyond the Standard Model that currently remain as elusive as science-fiction.
First among these - highlighted in Nobel acceptance comments by Englert - is super-symmetry, the theory that all basic particles have a heavier but invisible partner, which is linked to concepts like string theory and extra dimensions.
No sign of super-symmetry has yet appeared in CERN's collider, leading some science writers to voice doubts about the concept.
But Heuer said that just because it was elusive did not mean it did not exist. "It took us 30 years to find the Higgs," he added.
The LHC, in its 27-kilometre (17-mile) circular tunnel under a corner of Switzerland and France, was conceived in the early 1990s at a time when particle physicists, astrophysicists and cosmologists were increasingly talking together.
The interchange between experts in once separate fields has brought theories about the universe and its nature - as well as what came before and whether there are parallel undetected worlds - into sharper focus.
This has also been fueled by the increasing power of telescopes, allowing scientists to detect indirectly that there must be some strange substance massing around the galaxies to keep them together. This has become known as dark matter because it cannot be seen, although its effects are evident.
Recent measurements by the European Space Agency's satellite-borne Planck telescope found dark matter accounted for 27 percent of the universe and the even more enigmatic dark energy - driving galaxies apart - 68.3 percent.
Visible matter in open space - galaxies, stars and planets - accounts for just 5 percent.
String theory says particles are in fact tiny oscillating strings that can appear differently depending on how they are viewed. It requires multiple extra dimensions that have yet to be detected.
The theory, which has partly morphed into the M-theory espoused by British scientist Stephen Hawking, has fierce critics. It also allows for parallel universes - a multiverse where universes spring into existence and die spontaneously.
"But proving that," says CERN theoretician James Wells, "won't come in our lifetime."
(Editing by Andrew Heavens)