QCD sum rule studies of s s {bar{s}} {bar{s}} tetraquark states with J^{PC} = 1^{+-}

Abstract

We apply the method of QCD sum rules to study the structure X newly observed by the BESIII Collaboration in the phi eta ^prime mass spectrum in 2.0–2.1 GeV region in the J/psi rightarrow phi eta eta ^prime decay. We construct all the s s {bar{s}} {bar{s}} tetraquark currents with J^{PC} = 1^{+-}, and use them to perform QCD sum rule analyses. One current leads to reliable QCD sum rule results and the mass is extracted to be 2.00^{+0.10}_{-0.09} GeV, suggesting that the structure X can be interpreted as an s s {bar{s}} {bar{s}} tetraquark state with J^{PC} = 1^{+-}. The Y(2175) can be interpreted as its s s {bar{s}} {bar{s}} partner having J^{PC} = 1^{--}, and we propose to search for the other two partners, the s s {bar{s}} {bar{s}} tetraquark states with J^{PC} = 1^{++} and 1^{-+}, in the eta ^prime f_0(980), eta ^prime K {bar{K}}, and eta ^prime K {bar{K}}^* mass spectra.