Understanding the non-trivial isoscalar pseudoscalar structures in the K_S K_Sπ⁰ spectra in the J/ψ radiative decay

2024/07/14 by Yin Cheng, Lin Qiu, Cheng, Yin +2
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2407.10234

openalex publication_date 2024/07/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01

Abstract

Initiated by the recent observation of a flattened lineshape of IJ^PC=00^-+ around 1.4∼ 1.5 GeV in the K_S K_S π⁰ invariant mass spectrum by BESIII, we make a systematic partial wave analysis of J/ψ→γη_X→ γKKπ based on an isobaric approach. We demonstrate that in the scenario of the first radial excitations of the isoscalar pseudoscalar from the KKπ threshold to about 1.6 GeV the non-trivial K_S K_S π⁰ invariant mass spectrum can be explained by the coupled-channel effects with the presence of the triangle singularity mechanism. It shows that a combined fit of the Dalitz plots, three-body and two-body spectra can be achieved which suggests that the one-state solution around 1.4∼ 1.5 GeV proposed before still holds well. In particular, we show that the coupled-channel effects between the three important quasi-two-body decay channels, K^*K+c.c., κK+c.c. and a₀(980)π, can be well described by taking into account the one-loop corrections in the isobaric approach. This is because the isoscalar pseudoscalar states are coupled to the K^*K+c.c. and a₀(980)π (κK+c.c.) channels via the P and S waves, respectively. As a consequence, the coupled-channel effects can be largely absorbed into the redefinition of the tree-level effective couplings with the transition amplitudes computed to the order of one-loop corrections. Then, the coupled-channel effects can be estimated by the contributions from the one-loop rescattering amplitudes in comparison with the tree-level ones, where we find that the rescattering contributions from the P-wave into the S-wave, or vice verse, are apparently suppressed in the kinematic region near threshold.

Related

• Evidence of κ particle in J/ψ→ K^*(892)⁰ K⁺ π^-
• Can the observed enhancement in the mass spectrum of p p in J/ψ→ γp p be interpreted by a possible p p bound state
• Scalar and tensor resonances in J/ψ radiative decays
• Observation of a narrow, near-threshold enhancement in the pp mass spectrum from radiative J/psi--> gamma pp decays
• Study of f₁(1420) and η(1405) in the decay J/ψ→ γπ⁰π⁰π⁰