Lepton

Key Stage 5

Meaning

Leptons are a type of fermion which are unaffected by the strong nuclear interaction.

About Leptons

Leptons are fundamental particles as they are not made of any smaller particles.

Leptons include:

• Electron - A type of lepton with a mass of 9.11x10^-31kg and a charge of -1.60x10^-19 Coulombs.
• Muon - A type of lepton often referred to as a 'heavy electron' same charge as an electron (-1.60x10^-19) Coulombs but a mass 206 times the mass of an electron.
• Neutrino - A type of lepton with zero charge and negligible mass.

Leptons are affected by the:

• Weak Nuclear Interaction
• Electromagnetic Interaction
• Gravitational Interaction

Conserved Quantities

Lepton	Charge/e	Strangeness	Baryon Number	Lepton Number
Electron	\(Q=-1\)	\(S=0\)	\(B=0\)	\(L=+1\)
Muon	\(Q=-1\)	\(S=0\)	\(B=0\)	\(L=+1\)
Tauon	\(Q=-1\)	\(S=0\)	\(B=0\)	\(L=+1\)
Neutrino	\(Q=0\)	\(S=0\)	\(B=0\)	\(L=+1\)
Positron	\(Q=+1\)	\(S=0\)	\(B=0\)	\(L=-1\)
Antimuon	\(Q=+1\)	\(S=0\)	\(B=0\)	\(L=-1\)
Antitau	\(Q=+1\)	\(S=0\)	\(B=0\)	\(L=-1\)
Antineutrino	\(Q=0\)	\(S=0\)	\(B=0\)	\(L=-1\)