  We consider the effective interaction of quarks with a new GeV-scale vector
particle that couples to electroweak gauge bosons by the so-called effective
Chern-Simons interaction. We call this particle the Chern-Simons (CS) boson. We
construct an effective Lagrangian of the CS boson interaction with quarks of
two different flavors. This interaction is given by a divergent loop diagram,
however, it turns out that the divergent part is equal to zero as a consequence
of the CKM matrix unitarity in the SM. Therefore, we are able to predict the
effective interaction of the CS boson with quarks of different flavors without
introducing new unknown parameters to the model, using only parameters of the
initial effective Lagrangian. Our result shows that the effective interaction
of the CS boson with down-type quarks is sufficiently stronger compared with
up-type quarks. Based on our results, we give a prediction for the production
of CS bosons in mesons decays. Branching fractions were obtained for the main
reactions of the CS production in meson decays. The results obtained will be
useful for searching for the long-lived GeV-scale CS boson in intensity
frontier experiments.
