Strange particles

Hadrons containing at least one strange quark. Strong interactions produce them readily, but they decay through weak interactions unusually slowly because strong decays often cannot conserve strangeness.

Strange quark: A quark of the second generation, with electric charge −1/3 and strangeness −1. Its presence gives strange particles their defining flavor quantum number.
Associated production: Particle production in which a new quantum number is balanced by producing particles with compensating values. Strange particles are commonly created in pairs or with other particles that balance total strangeness.
Kaon: A meson containing one strange or antistrange quark and one light quark or antiquark. Kaons were among the first strange particles discovered and display distinctive weak decays.
Kaon discovery: The discovery of kaons in cosmic-ray and accelerator experiments during the mid-twentieth century. Unexpectedly long-lived mesons provided early evidence for strange-particle behavior.
Charm quark: A quark of the second generation, with electric charge +2/3 and charm +1. It is another heavier-than-up-and-down flavor, but has different charge and quantum number.
Hadron: A composite particle made of quarks bound by the strong interaction. Strange particles are hadrons whose quark content includes a strange quark.
Conservation law: A rule stating that a physical quantity remains unchanged in specified interactions or processes. Strangeness conservation explains why strong production can be fast while strong decay is forbidden.
Lambda baryon: A baryon containing one up, one down, and one strange quark. Its delayed decay into a proton and pion helped establish strange-particle behavior.
V-particle: A neutral particle observed through its decay into two charged tracks forming a V-shaped image. V-shaped tracks exposed strange particles that traveled before decaying.
Bottom quark: A third-generation quark with electric charge −1/3 and bottomness −1. Bottom hadrons also undergo weak decays, but their defining flavor is not strangeness.

Linked from 8 pages