Scientists may have found a particle six times heavier than the Higgs bosonby Philip Ball / March 18, 2016 / Leave a comment
Read more: Will gravitational waves help us discover cosmic strings?
From here on, it’s mostly guesswork and empiricism for particle physics. Informed guesswork, naturally—no field of science is better adapted to doing theory with minimal experimental data to guide it. But now that the Higgs boson has completed the Standard Model—the enumeration of all known subatomic particles and the interactions between them—what comes next is unknown. It will be largely a question to what experiments turn up. And none comes with higher expectations than those conducted at CERN’s Large Hadron Collider, which is currently undergoing test runs after an upgrade to take its particle collisions to even higher energies. The LHC will begin collecting data again in April.
Many particle physicists are now hoping to find evidence for the favourite candidate theory that takes physics beyond the Standard Model, called supersymmetry. This posits a fundamental relationship between the two currently distinct families of particle types, called bosons and fermions. If it holds true, then every current particle has a supersymmetric partner, all of them as yet unseen. The LHC will be looking for signs of these.
But already the collider has supplied a tantalizing hint of something that nobody predicted. Last December, CERN physicists reported that proton-smashing in both of the LHC’s principal detector systems, called ATLAS and CMS, had discovered an anomaly in the signals measured at energies higher than those needed to make the Higgs boson. The implication is that this is the signature of some extremely massive particle—a real monster as these things go, six times heavier than the ponderous Higgs boson—that decays into two gamma rays.
What could it be? It’s characteristic of this field that, rather than scratching their heads, researchers have already produced a flood of potential explanations: nearly 300 papers have been written and posted online so far. One might interpret that as an indication that the theories of high-energy physics are fluid and unconstrained enough to…