$$\varvec{J/\psi }$$ decays into $$\omega (\phi ) f_1(1285)$$ and $$\omega (\phi ) ``f_1(1420)$$”

Abstract

We perform a theoretical study of the $$J/\psi \rightarrow \omega (\phi ) K^* \bar{K} + c.c. \rightarrow \omega (\phi ) K^0 \pi ^+ K^-$$ J / ψ → ω ( ϕ ) K ∗ K ¯ + c . c . → ω ( ϕ ) K 0 π + K - reactions with the assumption that the $$f_1(1285)$$ f 1 ( 1285 ) is dynamically generated from a single channel $$K^* \bar{K} + c.c$$ K ∗ K ¯ + c . c interaction in the chiral unitary approach. Two peaks in the $$K^0 \pi ^+ K^-$$ K 0 π + K - invariant mass distribution are observed, one clear peak locates at the $$f_1(1285)$$ f 1 ( 1285 ) nominal mass, the other peak locates at around $$1420 \text {MeV}$$ 1420 MeV with about $$70 \text {MeV}$$ 70 MeV width. We conclude that the former peak is associated with the $$f_1(1285)$$ f 1 ( 1285 ) and the latter peak is not a genuine resonance but a manifestation of the kinematic effect in the higher energy region caused by the $$K^* \bar{K} + c.c.$$ K ∗ K ¯ + c . c . decay mode of the $$f_1(1285)$$ f 1 ( 1285 ) .