The CMS experiment at CERN

The 21-metre-long CMS detector has detected a shower of subatomic particles that were created by smashing protons together. Credit: Maximilien Brice/CERN

Particle physics

Physicists cheer rendezvous of Higgs boson and top quark

Encounters between two subatomic particles support reigning theory.

For the first time, physicists have measured the interaction of the two heaviest fundamental particles known in the subatomic world.

The standard model of particle physics explains the Universe in terms of a small number of fundamental forces, which both act on and are transmitted by a set of fundamental particles. Among those particles is the Higgs boson, which was found in 2012 and helps to explain why particles have mass.

Seeking a deeper understanding of the Higgs boson’s properties, researchers examined data from the Large Hadron Collider at CERN, Europe’s particle-physics laboratory near Geneva in Switzerland. The members of the CMS Collaboration used a specialized detector to study the particle fragments created when the collider smashes protons into each other at high speeds. The team measured production of the Higgs alongside top quarks and the quarks’ antimatter counterparts.

The observations showed directly — for the first time — that the strength of the interactions between the Higgs and the top quark is consistent with the expectation of standard model.