Decoding the structure near the π + π − mass threshold in ψ ( 3686 ) → J / ψ π + π − decays
Abstract
In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition ψ ( 3686 ) → J / ψ π + π − . The strong pion-pion final-state interactions are taken into account model independently by using dispersion theory. We find that we can reproduce the substructure near the π + π − threshold observed experimentally without introducing an extra resonance state. While a helicity-flip amplitude plays an important role for the formation of the dip in the invariant-mass distribution, the virtual exchange of the charmoniumlike exotic Z c ( 3900 ) state improves the fit quality only slightly.
Fields of Study & Subjects
Quantum Chromodynamics and Particle Interactions
Particle physics theoretical and experimental studies
High-Energy Particle Collisions Research
Publication details
- Journal / source
- Physical review. D/Physical review. D.
- Publisher
- American Physical Society (APS)
- Volume
- 113
- Issue
- 5
- Publication date
- 23 February 2026
- Language
- EN