References & Citations
High Energy Physics - Phenomenology
Title: Triangle singularity in the $J/ψ\to φπ^+ a_0^-(π^- η),\; φπ^- a_0^+(π^+ η)$ decays
(Submitted on 27 Feb 2024 (v1), last revised 24 Apr 2024 (this version, v2))
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.
Submission history
From: Wei-Hong Liang [view email][v1] Tue, 27 Feb 2024 15:15:18 GMT (847kb,D)
[v2] Wed, 24 Apr 2024 15:59:31 GMT (851kb,D)
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