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Triangle singularity in the $J/\psi \to \phi \pi^+ a_0^-(\pi^- \eta),\; \phi \pi^- a_0^+(\pi^+ \eta)$ decays
- Publication Year :
- 2024
-
Abstract
- We study the $J/\psi \to \phi \pi^+ a_0(980)^- (a_0^- \to \pi^- \eta)$ decay, evaluating the double mass distribution in terms of the $\pi^- \eta$ and $\pi^+ a^-_0$ invariant masses. We show that the $\pi^- \eta$ mass distribution exhibits the typical cusp structure of the $a_0(980)$ seen in recent high statistics experiments, and the $\pi^+ a^-_0$ spectrum shows clearly a peak around $M_{\rm inv}(\pi^+ a^-_0)=1420 \,{\rm MeV}$, corresponding to a triangle singularity. When integrating over the two invariant masses we find a branching ratio for this decay of the order of $10^{-5}$, which is easily accessible in present laboratories. We also call attention to the fact that the signal obtained is compatible with a bump experimentally observed in the $\eta \pi^+\pi^-$ mass distribution in the $J/\psi \to \phi \eta \pi^+\pi^-$ decay and encourage further analysis to extract from there the $\phi \pi^+ a_0^-$ and $\phi \pi^- a_0^+$ decay modes.<br />Comment: 8 pages, 3 figures; V2: discussion added, references added, version to appear in Phys. Rev. D
- Subjects :
- High Energy Physics - Phenomenology
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.2402.17584
- Document Type :
- Working Paper