The weak charged current couples a W boson to two members of a left-handed electroweak doublet. In the quark mass basis its flavor coefficients are entries of the Cabibbo-Kobayashi-Maskawa matrix.
Charged current refers to the type of current that is associated with the weak nuclear force, one of the four fundamental forces in physics. In the context of particle physics, charged currents are involved in interactions that change the type (or flavor) of particles, such as transforming a neutron into a proton or an electron into a neutrino. In weak interactions, charged currents are mediated by the exchange of W bosons (specifically, the W+ and W- bosons).
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