Collision course

摘要

Largely unnoticed at the weekend, the Large Hadron Collider (LHC), the world's most powerful particle accelerator, ended one hell of a run. Since March, protons had been whizzing more-or-less continuously around the colliders 27-kilometre ring, located at CERN, Europe's premier high-energy laboratory on the French-Swiss border near Geneva. At four points around the ring, protons collide at near-light-speed. The energies released are high enough to briefly create heavy particles, and physicists have been hoping for one above all others — the Higgs. The Higgs boson is a missing bolt in the standard model of particle physics. In popular parlance, it is known as the particle that gives all other particles mass. However, physicists like the Higgs (and its associated field) because the particle provides an elegant way to combine electromagnetism with the weak nuclear force. Such a step would create a single electroweak theory that is stronger than its two parts. It would also consolidate the four known forces into three — bringing researchers closer to an ultimate theory of everything. There are good reasons to hope that the Higgs is there, but nothing in nature requires it. Already in August, physicists saw one possible signal sink from view.