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The simplest Feynman diagram for beta decay. It contains a charged current interaction at each vertex. Charged current interactions are the most easily detected class of weak interactions. The weak force is best known for mediating nuclear decay. It has very short range, but is the only force (apart from gravity) to interact with neutrinos.
The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate W − boson. The W and Z bosons are carrier particles that mediate the weak nuclear force, much as the photon is the carrier particle for the electromagnetic force.
In contrast, a charged pion can only decay through the weak interaction, and so lives about 10 −8 seconds, or a hundred million times longer than a neutral pion. [10] (p30) A particularly extreme example is the weak-force decay of a free neutron, which takes about 15 minutes. [10] (p28)
Electromagnetism and the weak force are now understood to be two aspects of a unified electroweak interaction — this discovery was the first step toward the unified theory known as the Standard Model. In the theory of the electroweak interaction, the carriers of the weak force are the massive gauge bosons called the W and Z bosons.
In particular, under weak isospin SU(2) transformations the left-handed particles are weak-isospin doublets, whereas the right-handed are singlets – i.e. the weak isospin of ψ R is zero. Put more simply, the weak interaction could rotate e.g. a left-handed electron into a left-handed neutrino (with emission of a W − ), but could not do so ...
The nuclear force is distinct from what historically was known as the weak nuclear force. The weak interaction is one of the four fundamental interactions, and plays a role in processes such as beta decay. The weak force plays no role in the interaction of nucleons, though it is responsible for the decay of neutrons to protons and vice versa.
The Feynman diagram calculations, which are a graphical representation of the perturbation theory approximation, invoke "force mediating particles", and when applied to analyze high-energy scattering experiments are in reasonable agreement with the data. However, perturbation theory (and with it the concept of a "force-mediating particle ...
Weak neutral current interactions are one of the ways in which subatomic particles can interact by means of the weak force. These interactions are mediated by the Z boson . The discovery of weak neutral currents was a significant step toward the unification of electromagnetism and the weak force into the electroweak force , and led to the ...