Leptons

The leptons(light particles) makes one of the groups of elementary(subatomic) particles.

They belongs to fermions. They have seminumerical spin. It participates in weak interactions, but they do not form interactions with strong nuclear force. Leptons have an integer charge number and it is not possible to divide them further.

Types of leptons and generation
The leptons are divided into negatively charged(electrons e-, mion μ- and tauon τ-) and neutrally charged-neutrino(electron neuttrino ve, muons neutrino vm, tauon neutrino vt). Antiparticles exist for each lepton. It is called antilepton. Leptons are sorted into generation.

The first generation insludes an electron( mass 1me) and neutrino. It is the most famouse a the most enhanced particle.

The second generation contains mion( mass 207me) and its neutrino. They arise in atmosphere. They fall on Earth and we can detect them even deep below sea level.

The third generation contains tauon(mass 3484 me) and its neutrino. They have a the shortest half-life and they break down into lighter leptones and hadrons.

The lepton number
Leptons and antileptones are charakcterized by leptone´s number L. It represent the difference of quantity of leptons and antileptons in a particle reaction. Leptone has a value L=+1 while antilepton has a value L=-1. This value always remains preserved( law of conservation of lepton number). Lepton arises at formation of an antilepton and vice versa. Extinction works similarly.