Multichannel calculation of excited vectorϕresonances and theϕ(2170)

Abstract

A multichannel calculation of excited J P C = 1 −− φ states is carried out within a generalization of the Resonance-Spectrum Expansion, which may shed light on the classification of the φ(2170) resonance, discovered by BABAR and originally denoted X(2175). In this framework, a complete spectrum of bare ss states is coupled to those OZI-allowed decay channels that should be most relevant for the considered energy range. The included S-and P -wave two-meson channels comprise the lowest pseudoscalar, vector, scalar, and axial-vector mesons, while in the qq sector both the 3 S1 and 3 D1 states are coupled. The only two free parameters are tuned so as to reproduce mass and width of the φ(1020), but come out reasonably close to previously used values. Among the model's Tmatrix poles, there are good candidates for observed resonances, as well other ones that should exist according to the quark model. Besides the expected resonances as unitarized confinement states, a dynamical resonance pole is found at (2186 − i246) MeV. The huge width makes its interpretation as the φ(2170) somewhat dubious, but further improvements of the model may change this conclusion.

The three-body structure of the X(2175) and the Y(4260) states

“…This resulted into a peak in the cross section around 2175 MeV in accordance with the experimental cross sections obtained by different experimental groups [14]. Similar findings have also been reported in [19,20].…”

KΛ(1405)configuration of theKK̄Nsystem

“…The same formalism applied to the ππN system and its coupled channels revealed the dynamical generation of the N * (1710), N * (2100) and ∆(1910) [3]. The X(2175) state, reported by different experimental groups [4,5] in the φf 0 (980) invariant mass, has been explained as a φKK resonance with KK forming the f 0 (980) resonance [6][7][8].…”

Possible partner state of the Y(2175)

“…By using similar approaches, the Yð2175Þ was interpreted as a dynamically generated resonance by the self-interactions between the ϕ and f 0 ð980Þ resonances [29], while the resonance spectrum expansion formalism by including the f 0 ð980Þ as a resonance in the coupled ππ-KK system is also able to generate the Yð2175Þ in the ϕf 0 ð980Þ channel [30].…”