Tau (particle) Tau (particle) The tau (τ), also called the tau lepton, tau particle, or tauon, is an elementary particle similar to the electron, with negative electric charge and a spin of. Together with the electron, the muon, and the three neutrinos, it is a lepton. Like all elementary particles with half-integer spin, the tau has a corresponding antiparticle of opposite charge but equal mass and spin, which in the tau's case is the antitau (also called the "positive tau"). Tau particles are denoted by and the antitau by . Tau leptons have a lifetime of and a mass of (compared to
Alan (given name) what is today Brittany, France. An early figure who bore the name was St Alan, a 5th-century bishop of Quimper. This saint became a cult figure in the Brittany during the Middle Ages. Another early bearer of the name was St Alan, a 6th-century Cornish saint, who has a church dedicated to his memory in Cornwall (for example see St Allen, a civil parish in Cornwall named after this saint). Today the use of the given name (and its variants) is due to its popularity among the Bretons who imported the name to England, to Cornwall, and later to Ireland.