Study of the e⁺e^-→ J/ψ π⁺π^- lineshape near the D^*D+c.c. threshold and possible signals for exotic hidden charm states

2026/03/31 by Jun Wang, Qiang Zhao
Physics and Astronomy · #hep-ph

paper · pdf

10 pages and 4 eps figures; version to appear in PRD

arxiv created 2026/08/06 · arxiv updated 2026/08/07

Abstract

We investigate the lineshape of the e⁺e^-→ J/ψ π⁺π^- cross section in the vicinity of the D^*D+c.c. threshold, where the ``so-called'' G(3900) is observed in the e⁺e^-→ DD channel. To take into account the possible D^*D+c.c. open channel effects or possible contributions from G(3900), we include the intermediate meson loop transitions in e⁺e^-→ J/ψ π⁺π^-. As a consequence, a triangle singularity (TS) is fulfilled which can produce nontrivial structures in the J/ψπ invariant-mass spectrum. Moreover, the TS transition also allows access to exotic quantum number of (I,J^P(C))=(1,1^-(-)) in the J/ψπ invariant-mass spectrum. We present predictions for the J/ψ π invariant-mass spectrum and our results clarify the different manifestations of the kinematic effects and genuine resonances. In particular, we show that resonance structures arising from the P-wave DD scatterings or hidden charm tetraquark state with (I,J^P(C))=(1,1^-(-)) can be identified by the J/ψπ invariant mass spectrum. It can provide a theoretical guidance for future experimental search for these exotic candidates.

Citations

• A short review of the vector charmonium-like state ψ(4230)
• Resolving the polarization puzzles in D⁰→ VV
• Explaining the Many Threshold Structures in the Heavy-Quark Hadron Spectrum
• P_c(4312)⁺, P_c(4380)⁺, and P_c(4457)⁺ as double triangle cusps
• Threshold cusps and triangle singularities in hadronic reactions
• Visible narrow cusp structure in Λ_c⁺→ p K^- π⁺ enhanced by triangle singularity
• Internal particle width effects on the the triangle singularity mechanism in the study of the η(1405) and η(1475) puzzle
• Pentaquark and Tetraquark states
• The impact of S-wave thresholds D_s1D_s+c.c. and D_s0D^*_s+c.c. on vector charmonium spectrum
• Determination of spin and parity of the Z_c(3900)
• Hadronic molecules
• Precise measurement of the e⁺e^-→ π⁺π^-J/ψ cross section at center-of-mass energies from 3.77 to 4.60 GeV
• The "a₁(1420)" peak as the πf₀(980) decay mode of the a₁(1260)
• Remarks on the P_c structures and triangle singularities
• Exotic vector charmonium and its leptonic decay width
• Understanding the nature of the heavy pentaquarks and searching for them in pion-induced reactions
• Searching for charmoniumlike states with hidden ss
• Understanding the newly observed heavy pentaquark candidates
• How to reveal the exotic nature of the P_c(4450)
• Searching for observable effects induced by anomalous triangle singularities
• Triangle Singularities and XYZ Quarkonium Peaks
• Could the near-threshold XYZ states be simply kinematic effects?
• Z(4430)and a new paradigm for spin interactions in tetraquarks
• Influence of threshold effects induced by charmed meson rescattering
• Y(4260) as the first S-wave open charm vector molecular state?
• Y(4260) and Y(4360) as mixed hadrocharmonium
• Systematic study of the singularity mechanism in heavy quarkonium decays
• Study of e⁺ e^- → π⁺ π^- J/ψ and Observation of a Charged Charmonium-like State at Belle
• Decoding the riddle of Y(4260) and Z_c(3900)
• Isospin breaking andf0(980)-a0(980)mixing in theη(1405)→π0f0(980)reaction
• The puzzle of anomalously large isospin violations in η(1405/1475)→ 3π
• Effect of charmed meson loops on charmonium transitions
• Towards a dynamical understanding of the non-D D decay of ψ(3770)
• Hadro-Charmonium
• Gluonic charmonium resonances at BaBar and Belle?
• Four Quark Interpretation of Y(4260)
• Final State Interactions in Hadronic B Decays
• Phenomenology of Heavy Meson Chiral Lagrangians
• Singularities in the physical region