## VirtualBoson

`VirtualBoson` is an option for `PolarizationSum` and `DoPolarizationSums`. If set to True, FeynCalc will not complain when you apply the gauge trick (i.e. replace the polarization sum by $- g^{\mu \nu}$ for a particle that is not massless. This is useful when computing processes that involve a virtual photon as an external state.

### See also

[Overview](Extra/FeynCalc.md), [PolarizationSum](PolarizationSum.md), [DoPolarizationSums](DoPolarizationSums.md).

### Examples