# axial and vector resonances in composite higgs models

Is there a reason to believe that the axial resonances be heavier than the vector resonances in the composite higgs models?

For instance, in http://arxiv.org/abs/0808.2071, to have zero tree level contributions to S parameter, the constrain on the wave function mixing parameter $\epsilon$, makes axial resonances lighter. However, models constructed with CCWZ formalism, seem to favor heavier axial resonances as compared to the $\rho$'s.

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