The next couple of years will be make or break for the next big theory in physics called supersymmetry – SUSY for short. It might make way for a rival idea which predicts the existence of a ‘fifth force’ of nature. Next Spring, when the Large Hadron Collider (LHC) resumes its experiments, scientists will be looking for evidence of SUSY. It explains an awful lot that the current theory of particle physics does not. But there is a growing problem, provocatively expressed by Nobel Laureate George Smoot: “supersymmetry has got symmetry and it’s super but there is no experimental data to suggest it is correct.”
According to the simplest versions of the theory, supersymmetric particles should have been discovered at the LHC by now. One set of null results prompted Prof Chris Parkes, of the LHCb to quip: “Supersymmetry may not be dead but these latest results have certainly put it into hospital”. But other forms of the theory are still very much in play. Next year will be an important year for SUSY. The LHC will be smashing atoms together at almost twice the energy it did in its first run. Even those who are still strong advocates of SUSY, such as Cern’s revered professor of theoretical physics, John Ellis, agree that if LHC scientists do not find super particles in the LHC’s second run, it might be time for the hospital patient to be moved to the mortuary.
“If it is not found in LHC run two then there will be relatively few corners it could hide,” he told BBC News. “I know that at that point the community may decide that the guys who predicted supersymmetry are dying off like flies and that young guys will be interested in different types of theories and supersymmetry may be forgotten. But I don’t think we are at that point yet.” One of those young guys is Thibaut Mueller, a 24-year-old PhD student at Cambridge University. He is already checking out alternatives to SUSY. “A few years ago we thought it was a case of who will be first to find supersymmetry,” he said. “Now there is less and less focus on it and more people are starting to branch out into other models.”
Mr Mueller’s PhD looks at an alternative to supersymmetry called the composite Higgs model. This idea has been around for decades but is undergoing a resurgence as some researchers raise questions over supersymmetry. Physicists will be looking for evidence for it in the next run of the LHC in 2015. More here LHC scientists to search for ‘fifth force of Nature’.