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Leptons do not interact via the strong interaction. Their respective antiparticles are the antileptons , which are identical, except that they carry the opposite electric charge and lepton number. The antiparticle of an electron is an antielectron, which is almost always called a " positron " for historical reasons.
The name lepton comes from the Greek λεπτός leptós, "fine, small, thin" (neuter nominative/accusative singular form: λεπτόν leptón); [14] [15] the earliest attested form of the word is the Mycenaean Greek 𐀩𐀡𐀵, re-po-to, written in Linear B syllabic script. [16] Lepton was first used by physicist Léon Rosenfeld in 1948: [17]
Half of the fermions are leptons, three of which have an electric charge of −1 e, called the electron (e −), the muon (μ −), and the tau (τ −); the other three leptons are neutrinos (ν e, ν μ, ν τ), which are the only elementary fermions with neither electric nor color charge. The remaining six particles are quarks (discussed below).
These lists detail all known and predicted baryons in total angular momentum J = 1 / 2 and J = 3 / 2 configurations with positive parity. [5]Baryons composed of one type of quark (uuu, ddd, ...) can exist in J = 3 / 2 configuration, but J = 1 / 2 is forbidden by the Pauli exclusion principle.
In particle physics, lepton number (historically also called lepton charge) [1] is a conserved quantum number representing the difference between the number of leptons and the number of antileptons in an elementary particle reaction. [2]
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1932 Antielectron (or positron), the first antiparticle, discovered by Carl D. Anderson [13] (proposed by Paul Dirac in 1927 and by Ettore Majorana in 1928) : 1937 Muon (or mu lepton) discovered by Seth Neddermeyer, Carl D. Anderson, J.C. Street, and E.C. Stevenson, using cloud chamber measurements of cosmic rays [14] (it was mistaken for the pion until 1947 [15])
The Standard Model recognizes two types of elementary fermions: quarks and leptons. In all, the model distinguishes 24 different fermions. In all, the model distinguishes 24 different fermions. There are six quarks ( up , down , strange , charm , bottom and top ), and six leptons ( electron , electron neutrino , muon , muon neutrino , tauon and ...