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Fermions have half-integer spin; for all known elementary fermions this is 1 / 2 . All known fermions except neutrinos, are also Dirac fermions; that is, each known fermion has its own distinct antiparticle. It is not known whether the neutrino is a Dirac fermion or a Majorana fermion. [4] Fermions are the basic building blocks of all ...
This is a timeline of subatomic particle discoveries, including all particles thus far discovered which appear to be elementary (that is, indivisible) given the best available evidence. It also includes the discovery of composite particles and antiparticles that were of particular historical importance. More specifically, the inclusion criteria ...
The number of protons in the observable universe is called the Eddington number. In terms of number of particles, some estimates imply that nearly all the matter, excluding dark matter, occurs in neutrinos, which constitute the majority of the roughly 10 86 elementary particles of matter that exist in the visible universe. [11]
Six of the particles in the Standard Model are quarks (shown in purple). Each of the first three columns forms a generation of matter. The Standard Model is the theoretical framework describing all the known elementary particles. This model contains six flavors of quarks (q), named up (u), down (d), strange (s), charm (c), bottom (b), and top ...
The results are incorporated into the Standard Model, which describes all the known particles (there are currently 31, including the Higgs boson) and three of the four known fundamental forces ...
Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation.The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the study of combination of protons and neutrons is called nuclear physics.
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetic, weak and strong interactions – excluding gravity) in the universe and classifying all known elementary particles.
Because of momentum conservation laws, the creation of a pair of fermions (matter particles) out of a single photon cannot occur. However, matter creation is allowed by these laws when in the presence of another particle (another boson, or even a fermion) which can share the primary photon's momentum. Thus, matter can be created out of two photons.