#fermion  any particle that obeys Fermi-Dirac statistics and is subject to the Pauli exclusion principle
  supertype:  #particle  a body having finite mass and internal structure but negligible dimensions
  subtype:  #baryon__heavy_particle__heavyparticle  any of the elementary particles having a mass equal to or greater than that of a proton and that participate in strong interactions; a hadron with a baryon number of +1
     subtype:  #hyperon  any baryon that is not a nucleon; unstable particle with mass greater than a neutron
        subtype:  #lambda_particle__lambda_hyperon  an electrically neutral baryon with isotopic spin 1
     subtype:  #nucleon  a constituent (proton or neutron) of an atomic nucleus
        subtype:  #antineutron  the antiparticle of a neutron
        subtype:  #antiproton  an unstable negatively charged proton; the antiparticle of a proton
        subtype:  #neutron  an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus
        subtype:  #proton  a stable particle with positive charge equal to the negative charge of an electron
           subtype:  #hydrogen_ion  a positively charged atom of hydrogen; that is to say, a normal hydrogen atomic nucleus
  subtype:  #lepton  an elementary particle that participates in weak interactions; has a baryon number of 0
     subtype:  #electron__negatron  an elementary particle with negative charge
        subtype:  #delta_ray__deltaray  an electron ejected from matter by ionizing radiation
        subtype:  #free_electron  electron that is not attached to an atom or ion or molecule but is free to move under the influence of an electric field
        subtype:  #photoelectron  an electron that is emitted from an atom or molecule by an incident photon
        subtype:  #valence_electron__valenceelectron  an electron in the outer shell of an atom which can combine with other atoms to form molecules
     subtype:  #negative_muon__muon__mu-meson  an elementary particle with a negative charge and a half-life of 2 microsecond; decays to electron and neutrino and antineutrino
     subtype:  #neutrino  an elementary particle with zero charge and zero mass
     subtype:  #tauon__tau-minus_particle__tauminusparticle  a lepton of very great mass

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