THE HUNT FOR INVISIBLE PARTICLES IS OPENING A NEW SCIENTIFIC FRONTIER

The link between theory and experiment is opening a window on to the next iteration of physics

- DA ARTIE MACH

No one has ever seen a Higgs boson. In fact, of all the particles in the Standard Model of Particle Physics arguably only the photon (a particle of light) is, in any sense, visible. All the others - quarks, electrons, mu and tau leptons, neutrinos, gluons, and W and Z bosons are effectively invisible.

As for the Higgs boson, even indirectly inferring its existence took a 40-year search with the most complex machine ever built. Its discovery in 2012 at the Large Hadron Collider (LHC) was considered one of the most important advances of modern physics and a huge success of the Standard Model.

Using a combination of data from ATLAS and CMS, the LHC's two biggest detectors, the Higgs detection confirmed our picture of how fundamental particles (such as quarks and electrons) acquired the properties we measure today, and how the forces of nature arranged themselves in the early Universe.

Now that we have the Higgs, researchers at the LHC have been hoping to use it to better understand the Standard Model itself or, ideally, find a hint of 'new physics' that would indicate what kind of theory might replace it. But how do we study a particle we can't see? What are we really looking at? The answers are complicated, but they touch on something much deeper: the entanglement of theoretical models and experimental data.

DR KATIE MACK