Search results
Results from the WOW.Com Content Network
In particle physics, a pion (/ ˈ p aɪ. ɒ n /, PIE-on) or pi meson, denoted with the Greek letter pi (π), is any of three subatomic particles: π 0, π +, and π −. Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons. They are unstable, with the ...
The intrinsic parity of the pion is P = −1 (since the pion is a bound state of a quark and an antiquark, which have opposite parities, with zero angular momentum), and parity is a multiplicative quantum number. Therefore, assuming the parent particle has zero spin, the two-pion and the three-pion final states have different parities (P = +1 ...
In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks that give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)" , or the Eightfold Way , the successful classification scheme organizing the large number of lighter hadrons that ...
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.
For example, a positive pion (π +) is made of one up quark and one down antiquark; and its corresponding antiparticle, the negative pion (π −), is made of one up antiquark and one down quark. Because mesons are composed of quarks, they participate in both the weak interaction and strong interaction.
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 ...
Hence Ξ c, Ξ b, Ξ cc, Ξ cb, etc. Unless specified, the non-up/down quark content of Xi baryons is strange (i.e. there is one up or down quark and two strange quarks). However a Ξ 0 b contains one up, one strange, and one bottom quark, while a Ξ 0 bb contains one up and two bottom quarks. In 2012, the CMS experiment at the Large Hadron ...
All of the Δ baryons with mass near 1 232 MeV quickly decay via the strong interaction into a nucleon (proton or neutron) and a pion of appropriate charge. The relative probabilities of allowed final charge states are given by their respective isospin couplings. More rarely, the Δ + can decay into a proton and a photon and the Δ 0