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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.
The top quark, however, decays via the weak force with a mean lifetime of 5×10 −25 seconds. Unlike all other weak interactions, which typically are much slower than strong interactions, the top quark weak decay is uniquely shorter than the time scale at which the strong force of QCD acts, so a top quark decays before it can hadronize. [ 16 ]
A hadron is a composite subatomic particle.Every hadron must fall into one of the two fundamental classes of particle, bosons and fermions. In particle physics, a hadron (/ ˈ h æ d r ɒ n / ⓘ; from Ancient Greek ἁδρός (hadrós) 'stout, thick') is a composite subatomic particle made of two or more quarks held together by the strong interaction.
Hadron colliders produce particles that contain charm quarks at a higher cross section. [ c ] [ 81 ] The W boson can also decay into hadrons containing the charm quark or the charm antiquark. [ 82 ] The Z boson can decay into charmonium through charm quark fragmentation. [ 83 ]
The mechanism relies on the unitarity of the charged weak current flavor mixing matrix, which enters in the two vertices of a one-loop box diagram involving W boson exchanges. Even though Z 0 boson exchanges are flavor-neutral (i.e. prohibit FCNC), the box diagram induces FCNC, but at a very small level.
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 (
A visual representation of the division order of universal forces. In physical cosmology, the quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but the temperature of the universe was still too high to allow quarks to bind together ...
The top quark interacts with gluons of the strong interaction and is typically produced in hadron colliders via this interaction. However, once produced, the top (or antitop) can decay only through the weak force. It decays to a W boson and either a bottom quark (most frequently), a strange quark, or, on the rarest of occasions, a down quark. [a]