A fundamental particle, one of the six flavors of quarks, with a mass heavier than up and down quarks.The strange quark is one of the six fundamental flavors of quarks in the Standard Model of particle physics. It is the third-lightest quark, with a mass of about 95 MeV/c², which is roughly 20 times heavier than the up quark and 40 times heavier than the down quark. Because of its relatively short lifetime, it is not found in ordinary matter but is produced in high-energy particle collisions and in certain radioactive decays. Its existence was first inferred from the behavior of particles called 'strange' particles, which were produced copiously but decayed slowly, a puzzle that led to the concept of a new quantum number called 'strangeness'.
The concept of strangeness was introduced by Murray Gell-Mann and Kazuhiko Nishijima in 1953 to explain the unexpected properties of kaons and hyperons. The strange quark itself was incorporated into the quark model proposed by Gell-Mann and George Zweig in 1964.
The strange quark carries a quantum property called strangeness (S = -1), which is conserved in strong and electromagnetic interactions but violated in weak interactions. This explains why strange particles are produced in pairs (via the strong force) but decay singly (via the weak force), giving them a longer lifetime than expected. In modern particle physics, strange quarks are constituents of many hadrons, such as kaons and hyperons, and they play a role in the structure of the proton, contributing to its spin and mass through quantum fluctuations.
Strange quarks are studied in high-energy physics experiments, such as those at CERN's Large Hadron Collider, to test the Standard Model and search for new physics. They also play a role in astrophysics, where strange matter (containing strange quarks) is hypothesized to exist in the cores of neutron stars.
A 'strangelet' — a hypothetical bound state of roughly equal numbers of up, down, and strange quarks — was once feared to be a potential doomsday scenario, as it was speculated it could convert ordinary matter into strange matter, though this is now considered extremely unlikely.




