### particle

(very small thing)

Some particle-physics terms and associated characteristics:

 Particle term Spin Statistics Comment Examples fermion half-integer(1/2, 3/2, 5/2, ...) Fermi-Dirac Any particle with such spin;obeys Pauli exclusion principle;can be elementary particleor composite leptons, quarks, baryons boson integer(0, 1, 2, ...) Bose-Einstein Any particle with such spin;can be elementary particleor composite photon, gluon, W boson, Higgs bosonor a meson (a composite boson) lepton 1/2 Fermi-Dirac Type of elementary particleand a type of fermion electron, muon, neutrino quark 1/2 Fermi-Dirac Type of elementary particleand a type of fermion;subject to the strong force up, down, top, bottom, strange, charm hadron either integeror half-integer depends Any composite particle;can be a fermion or boson any baryon, any meson baryon 1/2 Fermi-Dirac Any composite particle made of three quarks;a type of hadron and a type of fermion protons, neutrons meson 0 or 1 Bose-Einstein Any composite particle made up of a quark and antiquark;a type of hadron and a type of boson;unstable: decays in a fraction of a second Pion, many other types
• spin - a quantum number indicating a type of quantum angular momentum.
• Pauli exclusion principle - a characteristic of some particles (i.e., those with half-integer spin) that two such particles are never in close association if all their quantum numbers are identical: an example is all the electrons within an atom.
• Fermi-Dirac statistics - a statistical distribution of energy levels of particles when they are in thermodynamic equilibrium if the particles are ruled by the Pauli exclusion principle (as opposed to Bose-Einstein statistics).
• quantum number - quantum mechanical values associated with a particle or system of particles: the set of them varies by system: they are conserved, i.e., changes to the particles don't change the total sums of any of the numbers. Electric charge and spin are examples. Net electric charge, for example, does not change in a particle interaction.
• strong force - one of the fundamental forces: the force that holds protons, neutrons, and atomic nuclei together.

Atomic nuclei, ions, and (neutral) atoms all fall under the category of hadron (composite particle) and can be either a fermion or boson, depending upon the constituents. Antimatter offers another dimension: some elementary particles have an associated antiparticle, e.g., a positron is an anti-electron, but both these two are leptons and fermions.

(physics,particles)
http://en.wikipedia.org/wiki/List_of_particles
http://en.wikipedia.org/wiki/Fermion
http://en.wikipedia.org/wiki/Boson
http://en.wikipedia.org/wiki/Lepton

Referenced by pages:
absorption
absorption coefficient
air shower
alpha particle
antimatter
atmospheric escape
axion (A0)
baryon acoustic oscillations (BAO)
baryon
beam
Bose-Einstein condensate (BEC)
beta decay
black hole (BH)
Blandford-Znajek mechanism (BZ process)
Boltzmann constant (k)
Boltzmann equation
Bose-Einstein statistics
bremsstrahlung
Boltzmann Transport Equation (BTE)
Cassini
cold dark matter (CDM)
chemical equilibrium (CE)
Cherenkov detector
CNO cycle
coherent light
collimator
column density
Compton scattering
Compton wavelength
cooling function
cosmic rays (CR)
cross section
dark matter
dark matter annihilation
de Broglie wavelength
decoupling
degeneracy weight
diffraction
diffusion
electron orbital
electron pressure
electron scattering
electron screening
electroweak
endothermic reaction
electron volt (eV)
exosphere
exotic star
Fokker-Planck equation
free streaming
freeze-out
fusion
fuzzy dark matter (FDM)
Galileo
Gamow peak
geodesic
Giotto
graviton
ground state
GZK limit
Hamiltonian
heating
heliosphere
Hough transform (HT)
International Cometary Explorer (ICE)
ideal gas law
interplanetary medium (IPM)
Jeans escape
Jeans parameter (λ)
JUICE
Juno
Kavli Institute
kinetic energy (KE)
lattice Boltzmann method (LBM)
Local Interstellar Cloud (LIC)
line shape function
Lorentz force
MACHO
magnetic field
magnetosphere
mass
Maxwell-Boltzmann distribution
Maxwell's equations
mean free path
Magnetospheric Multiscale Mission (MMS)
mole (mol)
neutralino
neutrino (ν)
neutron scattering
New Horizons (NF1)
nitrogen (N)
Orbiting Wide-angle Light Collectors (OWL)
pair production
PAMELA
particle horizon
particle spectrometer
partition function (Z)
Pauli exclusion principle
photodisintegration
photon
pion (π)
plasma
plasma frequency
parts per million (PPM)
pressure integral
pulsar (PSR)
Pioneer Venus Orbiter (PVO)
quantum field theory (QFT)
quark-gluon plasma (QGP)
quantum
quantum fluctuations
quantum mechanics (QM)
quantum mixing
quantum number
quantum tunneling
quark
quark matter (QM)
Rayleigh scattering
repulsive dark matter (RDM)
reheating
relativistic astrophysics
relativistic effect
relativistic speed
relic
scattering
Schrödinger-Poisson equation
scintillator
solar energetic particle (SEP)
superluminous supernova (SLSN)
Solar and Heliospheric Observatory (SOHO)
solar storm
solar wind
Solar Orbiter (SolO)
space weather
spark chamber
solar particle event (SPE)
spectrometer
spectrometry
spin (ms)
spinning dust emission
synchrotron self-Compton (SSC)
standard model
standard model of a flare
stellar structure
STEREO
Stokes number (Stk)
string theory
Sun surface features
supersymmetry (SUSY)
temperature
thermal bremsstrahlung
thermal emission
thermodynamic equilibrium (TE)
Thomson scattering
Ulysses
Heisenberg uncertainty principle
Van Allen belts
VHE
Vlasov-Poisson equation
Voyager
wave-particle duality
white dwarf (WD)
WIMP
ZEPLIN

Index