Strange quark
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| Composition: | Elementary particle |
| Family: | Fermion |
| Group: | Quark |
| Generation: | Second |
| Interaction: | Strong, Weak, Electromagnetic force, Gravity |
| Antiparticle: | Strange antiquark (s) |
| Theorized: | Murray Gell-Mann (1964) George Zweig (1964) |
| Symbol(s): | s |
| Mass: | 70–130 MeV/c2 |
| Decays into: | Up quark |
| Electric charge: | −1⁄3 e |
| Color charge: | Yes |
| Spin: | 1⁄2 |
The strange quark (originally called the sideways quark) is a second-generation quark with a charge of −(1/3)e and a strangeness of −1. It is the third-lightest quark after the up and down quarks, with a mass of somewhere between 80 and 130 MeV. The first strange particle (particle containing a strange-valence quark) was discovered in 1947, with the identification of the kaon, but the strange quark itself was not identified until Gell-Mann and Zweig developed the quark model in 1964.
[edit] Hadrons containing strange-valence quarks
Hadrons containing strange-valence quarks include the following:
- Kaons are mesons containing a strange quark (or its antiparticle) and an up or down quark.
- The η and η′ flavorless mesons are linear combinations of several quark-antiquark pairs, including the strange-antistrange.
- The φ flavorless meson is pure strange-antistrange.
- Strange baryons are known as hyperons: the Σs and Λs have one strange quark, the Ξs two, and the Ωs three.
[edit] See also
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