fermion in Catalan

(particle physics, Standard Model) Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any system of identical such particles changes sign whenever two are swapped); a baryon, a lepton or a quark;(slightly more loosely) any such particle or any composite particle composed of fermions.