Line-shape analysis of charmonium resonances

Abstract

We discuss weather the new enhancements found by BES, alias the $Y(4220)$, $Y(4260)$, $Y(4360)$, and $Y(4390)$ are true resonances. We argue that the nearby thresholds $D_s^{\ast }{\bar{D}}_s^{\ast }$, $D{\bar{D}}_1+\bar{D}{D}_1$, $D_s{\bar{D}}_{s1}+\overline{D_s}{D}_{s1}$ and $D^{\ast }{\bar{D}}_1+{\bar{D}}^{\ast }{D}_1$, as well as the $\psi (4160)$ and $\psi (4415)$ states have a strong influence over the observed $J/\psi {\pi }^{+}{\pi }^{-}$ and $h_c{\pi }^{+}{\pi }^{-}$ line-shapes. We propose an unitarized effective Lagrangian model to study the dynamical effect of the interaction between each known $\psi$ state and its closest thresholds. In addition, we present some of our recent motivating results, using the same model, for the $\psi (3770)$ resonance, where the distortion from a Breit-Wigner line-shape is shown to result not only from the kinematic interference, but also from the influence of the $D^0{\bar{D}}^0+D^{+}{D}^{-}$ one-loops. Moreover, two poles were found, at about 3.78 GeV and at 3.74 GeV, the second one generated dynamically, yet contributing to the distortion of the line-shape.

Proceedings of the Conference "Hadron 17", held on 25-29 September, 2017, in Salamanca, Spain

References in corpus (7)

• Dynamically Generated Open and Hidden Charm Meson Systems
• Precise measurement of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ cross section at center-of-mass energies from 3.77 to 4.60 GeV
• Evidence of Two Resonant Structures in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{h}_c$
• Measurement of the near-threshold $e^{+}{e}^{-}\to D\bar{D}$ cross section using initial-state radiation
• Measurements of the braching fractions for psi(3770)--> D0D0-bar,D+D-,DD-bar$ and the resonance parameters of psi(3770) and psi(2S)
• Interference effects in the X(4260) signal
• Line-shape and poles of the $\psi (3770)$

Cited by in corpus (1)

• Radially excited $\psi$ mesons and the $Y$ enhancements