After a spectacular first act, the Large Hadron Collider is taking an intermission break, shutting down on Feb. 11 for two years of construction and upgrades.
The list of important things that the LHC found in its initial run can be summed up in one word: Higgs. Though scientists remain a bit coy about calling the particle they found in July 2012 the Higgs boson (more data is needed to conclusively prove this) it is something that looks like the Higgs, acts like the Higgs, and was found where the Higgs was expected. Given that this long-sought boson is all but officially discovered, it can take its place as the final piece in the puzzle of physicists’ Standard Model – the established theory explaining the interactions of all known particles and forces.
While finding the Higgs has been a triumph concluding one generation of physicists wildest dreams, scientists can rightfully said to be a little disappointed. That’s because the LHC was not built just to hunt down one particular boson. It was meant to uncover a host of new subatomic particles and exotic phenomena. In this gallery, we will take a look at some of these hoped for events and what they might have meant for science had they been found.If the Higgs is all that the LHC discovers “it could be a huge disaster,” said theoretical physicist Lawrence Krauss of Arizona State University.
Getting a look at the Higgs was supposed to give scientists a glimpse of physics beyond the Standard Model, which has problems and holes that prevent it from being the final theory of everything. But the Higgs has been stubbornly normal, more or less what was expected from Standard Model predictions with barely a hint of anything revolutionary.
“All the important question remain unknown and we’re waiting for some new information about the Standard Model and which direction to go,” said Krauss.
In particular, physicists had by now hoped to see some evidence of a theory known as supersymmetry, which predicts the existence of an almost identical but heavier partner to every known subatomic particle. Supersymmetry elegantly solves many of the Standard Model’s problems but, as yet, there has been no real verification of its mechanisms and physicists are beginning to lose faith in the idea that actually exists.
But the possibility of seeing either supersymmetry or other new physics is not yet completely out of the question. When the LHC comes back online in December 2014, it will be colliding protons at twice the energy that it has so far achieved. This will allow scientists to probe higher and higher energy ranges and potentially see the particles and other forces that didn’t turn up during this initial run.
“Experimenters are clever and careful,” said physicist Martin Perl, who shared the Nobel Prize in 1995 for discovering the tau particle. “There’s a lot more to discover but we’ll have to wait and see.”
Image: A technician welding inside the beam tube at the Large Hadron Collider. CERN