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# 7.3: Weak Nuclear Force

This manifests itself through nuclear $$\beta$$ decay, $n\rightarrow p+e^{-}+\overline{\nu}_e.$ The standard coupling for this theory is called the Fermi coupling, $$G_F$$, after its discoverer. After the theory was introduced it was discovered that there were physical particles that mediate the weak force, the $$W^{\pm}$$ and the $$Z^0$$ bosons. These are very heavy particles (their mass is about 80 times the proton mass!), which is why they have such a small range – fluctuations where I need to create that much mass are rare. The $$W^{\pm}$$ bosons are charged, and the $$Z^0$$ boson is neutral. The typical $$\beta$$ decay referred to above is mediated by a $$W^-$$ boson as can be seen in the Feynman diagram in Figure $$\PageIndex{1}$$. The reason for this choice is that it conserves charge at each point (the charge of a proton and a $$W^-$$ is zero, the charge of an electron and a neutrino is -1, the same as that of a $$W^-$$).

Figure $$\PageIndex{1}$$: The Feynman diagram for the weak decay of a neutron.