Lepton number

In high energy physics, the lepton number is the number of leptons minus the number of antileptons.

Related Topics:
High energy physics - Lepton

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In equation form,

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::L = n_{ell} - n_{overline{ell}}

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so all leptons have assigned a value of +1, antileptons −1, and non-leptonic particles 0. Lepton number (sometimes also called lepton charge) is an additive quantum number, which means that its sum is preserved in interactions (compared to multiplicative quantum numbers as parity, where the product is preserved instead).

Related Topics:
Quantum number

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Besides to the leptonic number, leptonic family numbers are also defined:

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• the electronic number $L\_e$ for the electron and the electronic neutrino;
• the muonic number $L\_\{mu\}$ for the muon and the muonic neutrino;
• the tauonic number $L\_\{\; au\}$ for the tauon and the tauonic neutrino;

with the same asignation scheme than the leptonic number: +1 for particles of the corresponding family, −1 for the antiparticles, and 0 for leptons of other families or non-leptonic particles.

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Lepton number: Conservation laws for leptonic numbers ►