Building experimental evidence suggests that the electron, muon and tau may feel different forces. When the tau lepton was discovered in the 1970s, it didn’t resolve any outstanding mysteries—it ...

In the world of particle physics, you are never alone — quite literally. Every moment there is an invisible rainstorm of subatomic particles falling down on us from space. Unlike the kind of matter we ...

The discovery of the muon originally confounded physicists. Today international experiments are using the previously perplexing particle to gain a new understanding of our world. At the beginning of ...

The NA64 experiment started operations at CERN's SPS North Area in 2016. Its aim is to search for unknown particles from a hypothetical "dark sector." For these searches, NA64 directs an electron beam ...

Since the 1980s, the US government’s Chicago-area Fermilab has been at the forefront of high-energy physics. That’s in large part thanks to the Tevatron, the machine that first reached the energies ...

Leptons are elementary fermionic particles constituting a fundamental physical system in the Standard Model, characterized by half-integer spin (spin-½), lack of color charge, and participation in ...

(1) A beam of negatively charged muons is produced and injected into a mixed fuel of deuterium and tritium, (2) resulting in the creation of many muonic tritium atoms (tµ). As muons are 207 times ...