Did one observe couplings of right-handed quarks to W ?

I consider non standard EW couplings of light right-handed quarks to W and Z suggested in a systematic non decoupling bottom-up low-energy effective theory approach to possible extensions of the Standard Model. New experimental tests in K^L_{mu3} decays based on recent measurements and scalar form factor analysis are discussed. A successful NLO fit to the standard set of Z-pole and other NC data is presented as well.
Comment: 9 pages, 2 figures. Talk given at the KAON07 International Conference, May 21-25 2007, Frascati, Italy