The CMS experiment at CERN is the latest to weigh in on the mass of the W boson – an elementary particle that, along with the Z boson, mediates the weak force, which is responsible for a form of radioactivity and initiates the nuclear fusion reaction that powers the Sun.

At a seminar held at CERN today, the CMS collaboration reported how it has analysed proton–proton collision data from the second run of the Large Hadron Collider, the Laboratory’s flagship particle accelerator, to make its first mass measurement of this fundamental particle.