Nature of the vector resonance Y(2175)

Abstract

Spectroscopic parameters and decay channels of the vector resonance Y (2175) are studied by considering it as a diquark-antidiquark state with the quark content susu. The mass and coupling of the tetraquark Y (2175) are calculated using the QCD two-point sum rules by taking into account various quark, gluon and mixed condensates up to dimension 15. Partial widths of its strong decays to φf0(980), φη, and φη ′ are computed as well. To this end, we explore the vertices Y φf0(980), Y φη, and Y φη ′ , and calculate the corresponding strong couplings by means of the QCD light-cone sum rule method. The coupling G Y φf of the vertex Y φf0(980) is found using the full version of this method, and by treating the scalar meson f0(980) as a diquark-antidiquark tetraquark state. The couplings g Y φη and g Y φη ′ , however, are calculated by applying the soft-meson approximation to the light-cone sum rule method. Prediction for the mass of the resonance mY = (2173 ± 85) MeV is in excellent agreement with the data of the BaBar Collaboration [1], and within errors of calculations is compatible with the result reported by BESIII [2]. The full width Γ full = (91.1 ± 20.5) MeV of the Y (2175) saturated by its three strong decay channels is in a reasonable agreement with existing experimental data.Recently, we explored the light resonances X(2100) and X(2239) as the axial-vector and vector ssss tetraquarks [16], respectively. Besides spectroscopic parameters we also investigated the strong decays

Four-quark exotic mesons

“…An alternative suggestion on nature of this state was made in Ref. [200], where it was interpreted as a vector diquark-antidiquark system with the content sqsq . The resonances X(2100) and X(2239) (hereafter X 1 and X 2 , respectively) were explored as vector or axial-vector tetraquarks as well.…”

“…Then it appears that Y can be interpreted as a tetraquark with sqsq content. In this section, we provide results of our analysis, obtained in Ref [200]. by treating Y as a vector tetraquark [su][su] .…”

Measurement of $e^+ e^- \to ϕπ^+ π^-$ cross sections at center-of-mass energies from 2.00 to 3.08 GeV

“…This observation stimulated speculation that the φ(2170) resonance might be a strangeonium counterpart of the charmonium resonance ψ(4260) due to similarities in their production and decay pattern [8]. Considerable efforts have been made theoretically to understand the nature of the φ(2170) resonance and abundant interpretations have been proposed, including a traditional ss state [9][10][11][12][13][14], an ssg hybrid [8,15], an ssss tetra-quark state [16][17][18][19][20][21][22][23], a Λ Λ bound state [24][25][26][27][28] and an ordinary φK K or φf 0 (980) resonance produced by interactions between the final state particles [29,30]. The model predictions differ in both mass and width of the resonance.…”

Observation of a structure in e+e−→ϕη′ at s from 2.05 to 3.08 GeV

“…The ϕð2170Þ was discovered in the process e þ e − → ϕf 0 ð980Þ by BABAR [4,5] via the initial-state-radiation (ISR) technique, and was later confirmed by Belle [6], BES [7] and BESIII [8,9]. There are several interpretations of the ϕð2170Þ, including a regular ss meson in a 2 3 D 1 [10] or 3 3 S 1 configuration [11], an ssg hybrid [12,13], a tetraquark state [14][15][16][17][18], a ΛΛ bound state [19][20][21][22], an S-wave threshold effect [23], or a three-meson system ϕK þ K − [24]. The conventional ss meson is predicted to decay with significant fraction into the ss-signature modes ϕη and ϕη 0 [11].…”