Electrons and similar fermions {lepton}| share properties.
size
Leptons have diameter 10^-15 centimeter. Leptons have no internal structure, at least down to 10^-16 centimeter. Quantum electrodynamics requires leptons to be points.
forces
Weak nuclear force affects leptons, but strong nuclear force does not affect them. They have no color charge. Weak nuclear force causes one-quarter of lepton mass.
charge
Electron, muon, and tau particle leptons have charge -1 unit. Neutrinos have charge 0 units. Charge causes part of lepton mass. Lepton charge is sum of infinite negative charge, surrounded by positive-charge cloud induced by negative charge.
lifetime
Electrons cannot decay to smaller particles, so electrons have infinite lifetime.
isospin
Electrons, muons, and taus have weak-isospin third component -1/2, while all neutrinos have +1/2.
quarks
Quarks and leptons are similar. Both are point-like, pair, and have six types.
Negatively charged particles {electron}| rapidly orbit atomic nuclei at varying distances. Electron mass is 10^-27 grams or 0.511 MeV. Electron charge is -1. Lifetime is infinite. Protons equal electrons in neutral atoms. Electrons travel 10^-14 meters in 10^-8 seconds in one orbit.
Leptons {muon}| can be more massive than electrons. They can be in particles caused by cosmic rays hitting upper atmosphere. Muons have masses 204 times electron mass or 106 MeV. Lifetime is 2.2 x 10^-6 seconds, because muon can decay to electron. Muons have electric charge -1. Muon has associated neutrino. Muon has weak-isospin third component -1/2.
Atoms can have muons instead of electrons. Collisions can make two muons {dimuon event} or three muons {trimuon event}. These collisions demonstrate charmed particles and heavy leptons.
Leptons {neutrino}| can have almost no mass, zero charge, and half-integer spin.
types
Electrons {electron neutrino}, muons {muon neutrino}, and taus {tau neutrino} have neutrinos {flavor, neutrino}. Electron neutrinos have masses less than 54000 times electron mass. Muon neutrinos have masses less than 367 times muon mass. Tau neutrinos have masses less than 58 times tau mass. Neutrinos can change into each other, if neutrino mass is greater than 1 eV. Interaction with surrounding matter and energy causes neutrino masses to oscillate from electron to muon to tau neutrinos as they travel.
mass
Fewer neutrinos than expected come from Sun, because they have mass.
forces
Neutrinos do not feel strong force or electromagnetic force, only weak force and gravity. Neutrinos have two orthogonal linear-polarization states at 180-degree angle. Perhaps, weak force does not affect a possible fourth neutrino type {sterile neutrino}.
interactions
Because they have little mass and no charge, neutrinos pass through matter with few interactions. 10^12 neutrinos pass through people each second, because Sun radiation is 10% neutrinos.
antineutrino
Antineutrinos have one-third neutrino cross-sectional area.
Electron antiparticles {positron}| have +1 charge.
Leptons {tau particle}| {tauon} [found in 1975] can be heavier than muons. Tau particles have masses 3519 times electron mass or 1.78 GeV. Electric charge is -1. Lifetime is 0.3 x 10^-12 seconds, because tau can decay to electron. Tau has associated neutrino.
5-Physics-Matter-Particle-Subatomic-Fermion
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Date Modified: 2022.0225