Name: Vladyslav Shtabovenko Date: 12/18/14-05:31:51 PM Z


Dear FeynCalc users,

even though almost 13 years have passed since the original message from
Thomas, I think that it is worth pointing out that in FeynCalc 9
polarization vectors will not be transverse by default, i.e.

Pair[Momentum[Polarization[p, I]], Momentum[p]]

will not evaluate to zero. This should avoid unpleasant surprises and
make it easier to do computations with massive vector bosons. Of course,
the old behavior can be easily reenabled either by setting

SetOptions[Polarization, Transversality -> True]

to make all polarization vectors transverse, or via

Pair[Momentum[Polarization[p, I, Transversality -> True]],
  Momentum[p]]

to enforce transversality only for specific polarization vectors.

This change has been implemented in the development version in October
this year and is also mentioned on the news page

<https://github.com/FeynCalc/feyncalc/wiki/News>

Cheers,
Vladyslav