# Couplings of fields in the Standard Model

Could someone please explain what this task implies: Calculate coupling of fields: $\bar{e}_{R}e_{R}Z, HW^{+}W^{-}, W^{+}\bar{c}_{L}d_{L}$? (Exercise refers to the Standard Model Lagrangian). What do I technically have to do?

The coupling of $n$ fields refers to the constant in front of those n fields multiplied together in the Lagrangian. For example, the self coupling between two scalar fields in can be read off from the term $\mathcal{L} = \frac12 \lambda\phi^2$ as $\lambda$. In your example, you will need to expand all of the different terms in the Lagrangian as the coupling will not be as obvious.
In the standard model Lagrangian, you see only the bare fields (not physically observable), whereas you will need to expand your Lagrangian into the mixed state fields (for example $W^\pm = \frac{1}{\sqrt{2}}(W_1 \pm iW_2)$).