peak of the dashed and solid lines provides the branching ratio of the $f_1(1285)$ into $K \pi \bar K$ channel. As we see, it is of the order of 8%, the same value obtained in Ref. [@Aceti:2015pma] with a more elaborate model that we shall discuss below, and in agreement with experiment [@PDG].

Yet, what concerns us here is that the same mechanism produces a second peak around 1420 MeV as a consequence of the influence of the tail of the $f_1(1285)$ resonance and the increasing phase space for $K^* \bar K$ production. In Fig. \[Fig:4bis\] we can see in more detail the two peaks corresponding to $K\pi\bar K$ production. By assuming a smooth background below the second peak, as an experimental analysis would do, we induce that there is a resonant-like structure peaking around 1420 MeV with a width of about 60 MeV, the features observed in experiment when talking about the $f_1(1420)$ resonance. Yet, we did not have to invoke a new resonance for this structure, which appears naturally and unavoidably from the decay of $f_1(1285)$ into $K^* \bar K \to K \pi \bar K$. This also explains why the $f_1(1420)$ resonance is seen in the $K^* \bar 