Lindau, Germany: After the world’s largest atom smasher restarted in February, physicists in particular, and science buffs in general have been waiting for indicators from the mega machine if it’s any closer to solving some of the mysteries of the universe.
It’s likely that the early results will be discussed at the International Conference of High Energy Physics in Paris in July. But watching six Nobel laureates, each having contributed to the discipline of particle physics and cosmology, agreeing to disagree about their expectations from the Large Hadron Collider (LHC) on Tuesday in Lindau, it became apparent that the world of particle physics is as much dominated by subatomic structures as by gigantic personal perspectives.
Sergio Bertolucci, director for research and scientific computing at the European Nuclear Research Centre (CERN) in Geneva, told a 500-strong audience via video conferencing that the experiments and emerging results from the LHC were “perfectly placed to discover the known unknowns (such as dark matter, dark energy, Higgs particles, and so on). We are also confident of discovering the unknown unknowns (completely new particles that may be there).”
Step closer: An employee works on the LHC particle accelerator at CERN in Geneva, Switzerland. Adrian Moser/Bloomberg
The LHC has been built to examine some of the theories and observations about the universe, the most puzzling being the presence of dark matter and dark energy which constitute 96% of the universe, and which astronomers have managed to discover, but failed to describe.
It appears their description may not be coming anytime soon. “Dark matter is a magnificent discovery of astronomers,” said David Gross, winner of the 2004 Nobel Prize. He thinks the accelerator even has a good chance of producing it if it’s out there in the universe but “LHC will not be able to detect it because these particles are so small they will escape the detector”.
But John C. Mather, who along with George F. Smoot won the 2006 Nobel Prize for providing the first conclusive evidence that the universe originated from the hot, dense medium of the Big Bang, isn’t perturbed. He thinks very soon the astronomers in the US will have an opinion on how to pursue measurement of dark matter after an ongoing survey on some of these issues is completed in August. “But if David (Gross) is right then we are not going to get anything, whatever we may try to measure,” he said wryly.
Not quite as sceptical as Gross, Gerardus ’t Hooft, winner of the 1999 Prize, said there’s just a remote possibility of the LHC telling us anything about dark energy, which is 100 orders of magnitude smaller than anything what we now know of.
“If nothing but only Higgs (Boson) particle comes out of the LHC, it’d be great,” said Hooft. Although his wish centres around the particle accelerator “substituting the Standard Model”.
The Standard Model of particle physics describes the rules by which 12 elementary particles, four forces and 12 field particles that transmit these forces, work in unison. Developed in the mid-1970s, it has elegantly withstood the rigours of experimentation over time. But there are gaps in the model. For instance, it is unable to explain how elementary particles obtain their mass or why three families of such particles exist when only one seems to be required.
While everybody debated the hidden forces and material that pervade a large part of the universe, Martinus J.G. Veltman, winner of 1999 Prize, came up with a contrarian stand: “All hypotheses about dark matter are crazy.” As if giving up on LHC, he added, “Even Higgs particle is unlikely to come out of the accelerator.”
Theoretically, the Higgs particle exists to explain how elementary particles gain their mass.
Such varying views notwithstanding, CERN’s Bertolucci is very optimistic: “We are at the end of the Standard Model and (are) starting to put up some ground for that.” Tall claim it may sound to the outsiders, but this comes two days after the atom smasher beat all records for the most particle collisions. It doubled the previous rate to reach 10,000 particle collisions per second.
Smoot, who is credited with providing the evidence for dark matter and dark energy, summed it up: After 13.7 billion years of existence, the universe has become “a key lab for studies of new fundamental physics”.
The LHC, according to Smoot, is going to propel scientists in new directions. “We shouldn’t lose sight of the fact that this is our Columbus and we’ve been sailing for 50 years.”