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The weak interaction has a very short effective range (around 10 −17 to 10 −16 m (0.01 to 0.1 fm)). [b] [14] [13] At distances around 10 −18 meters (0.001 fm), the weak interaction has an intensity of a similar magnitude to the electromagnetic force, but this starts to decrease exponentially with increasing distance.
Consequently, the lightest particles containing a strange quark cannot decay by the strong interaction, and must instead decay via the much slower weak interaction. In most cases these decays change the value of the strangeness by one unit. This doesn't necessarily hold in second-order weak reactions, however, where there are mixes of K 0 and K ...
It also explains why weak interactions that change strangeness by 2 (ΔS = 2 transitions) are suppressed, while those that change strangeness by 1 (ΔS = 1 transitions) are allowed, but only in charged current interactions.
Two different neutral K mesons, carrying different strangeness, can turn from one into another through the weak interactions, since these interactions do not conserve strangeness. The strange quark in the anti-K 0 turns into a down quark by successively absorbing two W-bosons of opposite charge. The down antiquark in the anti-
In quantum mechanics, physicists often use the terms "force" and "interaction" interchangeably; for example, the weak interaction is sometimes referred to as the "weak force". According to the present understanding, there are four fundamental interactions or forces: gravitation, electromagnetism, the weak interaction, and the strong interaction ...
When they decayed through the weak interactions, they had lifetimes of around 10 −10 seconds. While studying these decays, Murray Gell-Mann (in 1953) [4] [5] and Kazuhiko Nishijima (in 1955) [6] developed the concept of strangeness (which Nishijima called eta-charge, after the eta meson (η)) to explain the "strangeness" of the longer-lived ...
Strangeness as a signature of QGP was first explored in 1983. [6] Comprehensive experimental evidence about its properties is being assembled. Recent work by the ALICE collaboration [7] at CERN has opened a new path to study of QGP and strangeness production in very high energy pp collisions.
Classifying these particles led him to propose that a quantum number, called strangeness, would be conserved by the strong and the electromagnetic interactions, but not by the weak interaction. [43] Another of Gell-Mann's ideas is the Gell-Mann–Okubo formula, which was, initially, a formula based on empirical results, but was later explained ...