Weak charge

In nuclear physics and atomic physics, weak charge refers to the Standard Model weak interaction coupling of a particle to the Z boson. For example, for any given nuclear isotope, the total weak charge is approximately −0.99 per neutron, and +0.07 per proton. It also shows an effect of parity violation during electron scattering.

This same term is sometimes also used to refer to other, different quantities, such as weak isospin, weak hypercharge, or the vector coupling of a fermion to the Z boson (i.e. the coupling strength of weak neutral currents).