- #1

Monaliza Smile

- 6

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I read in a QFT book that the free massive vector boson Lagrangian is

## \mathcal{L}_W = - \frac{1}{4} (\partial_\mu W^\dagger_\nu - \partial_\nu W_\mu^\dagger ) (\partial^\mu W^\nu - \partial^\nu W^\mu ) + M^2_W W^\dagger_\mu W^\mu ##

gives the propagator in momentum space by:

## i \Delta_{\mu\nu} = - i \frac{g_{\mu\nu - k_\mu k_\nu/M^2_W}}{k^2-M^2_W} ##

Any help how to derive the formula of the propagator from the Lagrangian ?