Search results
Results From The WOW.Com Content Network
Mesons named with the letter "f" are scalar mesons (as opposed to a pseudo-scalar meson), and mesons named with the letter "a" are axial-vector mesons (as opposed to an ordinary vector meson) a.k.a. an isoscalar vector meson, while the letters "b" and "h" refer to axial-vector mesons with positive parity, negative C-parity, and quantum numbers I G of 1 + and 0 − respectively.
All mesons are unstable, with the longest-lived lasting for only a few tenths of a nanosecond. Heavier mesons decay to lighter mesons and ultimately to stable electrons , neutrinos and photons . Outside the nucleus, mesons appear in nature only as short-lived products of very high-energy collisions between particles made of quarks, such as ...
Because mesons have integer spin (0 or 1) and are not themselves elementary particles, they are classified as "composite" bosons, although being made of elementary fermions. Examples of mesons include the pion, kaon, and the J/ψ. In quantum hadrodynamics, mesons mediate the residual strong force between nucleons.
A strange particle is an elementary particle with a strangeness quantum number different from zero. Strange particles are members of a large family of elementary particles carrying the quantum number of strangeness , including several cases where the quantum number is hidden in a strange/anti-strange pair, for example in the ϕ meson .
The strange quark or s quark (from its symbol, s) is the third lightest of all quarks, a type of elementary particle. Strange quarks are found in subatomic particles called hadrons. Examples of hadrons containing strange quarks include kaons (K), strange D mesons (D s), Sigma baryons (Σ), and other strange particles.
Despite the pseudoscalar mesons' masses being known to high precision, and being the most well studied and understood mesons, the decay properties of the pseudoscalar mesons, particularly of eta (η) and eta-prime (η ′), are somewhat contradictory to their mass hierarchy: While the η ′ meson is much more massive than the η meson, the η meson is thought to contain a larger component of ...
The background to the discovery of the J/ψ was both theoretical and experimental. In the 1960s, the first quark models of elementary particle physics were proposed, which said that protons, neutrons, and all other baryons, and also all mesons, are made from fractionally charged particles, the "quarks", originally with three types or "flavors", called up, down, and strange.
The estimated mass of the new particles was very rough, about half a proton's mass. More examples of these "V-particles" were slow in coming. The "k track plate" showing the three-pion decay mode of a kaon. The kaon enters from the left, and decays at the point labelled A