What is the g-factor of the W boson?

Question

Is there any experimental data available about the g-factor of the W boson?

Is there any theoretical prediction about its g-factor?

Answer 1

According to the Lagrangian of the Standard Model, the g-factor of the W-boson is given at tree level by $g=2$.

Experimental results are compatible with this result, see eg p4 of https://arxiv.org/abs/hep-ex/0407042 for results from LEP.

There are radiative corrections to the tree level value which can be computed in the Standard Model: $g=2+\dots$, but, as far as I understand, the precision of the experiments is still insufficient to be sensible to these corrections.

Answer 2

The g-factor is not a proper particle property, but depends on interactions involved and the "state of particle", in which it is calculated. In other words, the radiative corrections are state- (or process-) dependent.

Comments

The reference interactions are of course those of the electroweak QFT.