Baryons, hadrons, and non-zero-mass leptons {fermion}| have half-integer spins, with Fermi-Dirac statistics. No two fermions can have same quantum numbers. Fermion energy quanta always have same units. Same-type fermions are indistinguishable. For example, all electrons are exactly alike. Fermions and bosons account for all particles.
statistics
Bosons and fermions with the same quantum numbers are exactly the same, so two different photons or electrons with the same quantum numbers are exactly the same. Because they have no relativistic effects on each other, bosons have symmetric wave functions: f(b+) = f(b-), where b+ has spin +1 and b- has spin -1. Different bosons can have the same state, because bosons do not attract or repel each other by relativistic effects. Their changing fields are symmetrical and cancel. Because they have relativistic effects on each other, fermions have anti-symmetric wave functions: f(e+) = -f(e-), where e+ has spin +1/2 and e- has spin -1/2. For two fermions, wavefunction is anti-symmetric for fermion exchange: f(e+,e-) = -f(e-,e+). For helium atoms (with two electrons in lowest orbital), with no time changes, the ground-state wavefunction is anti-symmetric, but the main (zero-order) wavefunction is symmetric, so the spin wavefunction is anti-symmetric. Electrons with same spin cannot be in same state (Pauli exclusion principle), because f(e+,e+) = -f(e+,e+) can be true only if f(e+,e+) = 0. Different fermions have different states, because fermions repel each other by relativistic effects. Changing electric fields induce magnetic fields that affect moving electric charges. Their changing fields are anti-symmetrical and do not cancel.
Physical Sciences>Physics>Matter>Particle>Subatomic>Fermion
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Date Modified: 2022.0224