$J/\psi$ decays into $\omega (\varphi )f_1(1285)$ and $\omega (\varphi ){}^{\prime \prime }{f}_1(1420{)}^{\prime \prime }$

Abstract

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

17 pages, 5 figures; v2: discussion added, references added, version to appear in Eur.Phys.J.C