Polarization inχcJ→ϕϕdecays

Abstract

To understand the enhanced partial decay width for the decay of chi(c1) to the vector-meson pair phi phi recently observed by the BESIII collaboration, we suggest measuring the polarization parameter of the phi meson by analyzing the jointed angular distribution in the cascade decay e(+)e(-) -> psi(2S) -> gamma chi(cJ) -> gamma phi phi -> gamma 2(K+K-). The formulas to measure polarization parameters are presented, and they are estimated in the framework of perturbative QCD (pQCD) and the quark-pair-creation model. In pQCD we obtain results consistent with the expectation of the helicity selection rule. In the quark-pair-creation model, the parameter associated with the violation of the helicity selection rule is enhanced relative to that estimated in pQCD.