What do you mean by lepton number?
In particle physics, lepton number (historically also called lepton charge) is a conserved quantum number representing the difference between the number of leptons and the number of antileptons in an elementary particle reaction.
What is the lepton number of an electron?
Baryon Number Conservation
|Particle name||Symbol||Lepton number (Le)|
What is strangeness number?
Strangeness is the name given to the fifth quantum number. It was postulated (discovered) in 1953, by M. Of the six flavors of quarks, only the strange quark has a nonzero strangeness. The strangeness of nucleons is zero, because they only contain up and down quarks and no strange (also called sideways) quarks.
Do quarks have lepton numbers?
All quarks have baryon number B = 1/3, and all anti-quarks have baryon number B = -1/3. Everything else in the table besides the baryons and leptons is called a meson. Mesons are made up of a quark and an anti-quark. Mesons have L = 0 and B = 0, and they have no net leptons or baryons in their ultimate decay products.
Why is strangeness not conserved?
In our modern understanding, strangeness is conserved during the strong and the electromagnetic interactions, but not during the weak interactions. Consequently, the lightest particles containing a strange quark cannot decay by the strong interaction, and must instead decay via the much slower weak interaction.
What is the lightest lepton?
Electrons, the lightest leptons, have a mass only 1/1,840 that of a proton.
What is the strangeness of Sigma?
The sigma is a baryon which contains a strange quark. The quark composition of the three different sigmas is shown above. According to the Particle Data Book, the branching ratio for the decays of the sigma-plus is 51.57% for the pπ0 pathway and 48.31% for the nπ+ pathway.
How many leptons are there in the electron?
There are six leptons in the present structure, the electron, muon, and tauparticles and their associated neutrinos. The different varieties of the elementary particles are commonly called “flavors”, and the neutrinos here are considered to have distinctly different flavor.
Which is the lepton number of the neutrinos?
The lepton numbers Le, Lμ, and Lτ are violated separately, but the total lepton number L = Le + Lμ + Lτ is conserved. In this case the neutrinos ν i are the Dirac particles that possess the lepton number L = 1. The lepton number of the antineutrinos ν ¯ i is equal to −1.
Is the lepton number a multiplicative quantum number?
Lepton number is an additive quantum number, so its sum is preserved in interactions (as opposed to multiplicative quantum numbers such as parity, where the product is preserved instead). Mathematically, the lepton number is the number of antileptons. .
Which is an example of the conservation of lepton number?
The fact that the above decay is a three-particle decay is an example of the conservation of lepton number; there must be one electron neutrino and one muon neutrinoor antineutrino in the decay. The lifetimeof the muon is 2.20 microseconds. The muon is produced in the upper atmosphere by the decay of pionsproduced by cosmic rays: