Study of $e^{+}{e}^{-}\to h^{+}{h}^{-}J/\psi (h=\pi ,K,p)$ via initial-state radiation at Belle~II

Abstract

Using a data sample of 427.9 fb${}^{-1}$ collected by the Belle~II detector at or near the ${\rm Y}(4S)$ and ${\rm Y}(10753)$ resonances, the cross sections for $e^{+}{e}^{-}\to h^{+}{h}^{-}J/\psi$ $(h=\pi /K/p)$ at center-of-mass energies ranging from 3.8 GeV or the production threshold to 5.5/6.0/7.0 GeV have been measured via initial-state radiation. The cross sections for the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ and $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$ are consistent with previously published results. The cross sections for these channels obtained by combining with previous Belle results are also given. The process $e^{+}{e}^{-}\to p\bar{p}J/\psi$ is investigated for the first time. The yields are small and no significant structure is observed in the cross section versus energy. Searches for vector charmonium-like states in the $h^{+}{h}^{-}J/\psi$ systems, and for associated intermediate states in the $h^{\pm }J/\psi$ systems, are also presented.

Belle II Preprint: 2026-002 KEK Preprint: 2025-42

References in corpus (26)

• An Introduction to PYTHIA 8.2
• Multiquark Resonances
• Observation of a narrow pentaquark state, $P_c(4312{)}^{+}$, and of two-peak structure of the $P_c(4450{)}^{+}$
• An updated review of the new hadron states
• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Prediction of narrow $N^{\ast }$ and ${\Lambda }^{\ast }$ resonances with hidden charm above 4 GeV
• Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
• Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle
• Precise measurement of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ cross section at center-of-mass energies from 3.77 to 4.60 GeV
• Observation of a near-threshold structure in the $K^{+}$ recoil-mass spectra in $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{\ast 0}+D_s^{\ast -}{D}^0)$
• Observation of a $J/\psi \Lambda$ resonance consistent with a strange pentaquark candidate in $B^{-}\to J/\psi \Lambda \bar{p}$ decays
• Evidence for a new structure in the $J/\psi p$ and $J/\psi \bar{p}$ systems in $B_s^0\to J/\psi p\bar{p}$ decays
• Observation of the $Y(4230)$ and a new structure in $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$
• The Design, Construction, Operation and Performance of the Belle II Silicon Vertex Detector
• Measurement of $e^{+}{e}^{-}\to D_s^{(\ast )+}{D}_s^{(\ast )-}$ cross sections near threshold using initial-state radiation
• Observation of e+e- to K+K-J/psi via Initial State Radiation at Belle
• Observation of a vector charmoniumlike state in $e^{+}{e}^{-}\to D_s^{+}{D}_{s1}(2536{)}^{-}+c.c.$
• Observation of the $Y(4230)$ and evidence for a new vector charmonium-like state $Y(4710)$ in $e^{+}{e}^{-}\to K_S^0{K}_S^{0}J/\psi$
• Observation of a vector charmoniumlike state at 4.7 $\mathrm{GeV}/c^2$ and search for $Z_{cs}$ in $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$
• Measurement of the integrated luminosity of data samples collected during 2019-2022 by the Belle II experiment
• Observation of $e^{+}{e}^{-}\to \omega {\chi }_{bJ}(1P)$ and search for $X_b\to \omega {\rm Y}(1S)$ at $\sqrt{s}$ near 10.75 GeV
• Study of the resonance structures in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ process
• Evidence for a vector charmonium-like state in $e^{+}{e}^{-}\to D_s^{+}{D}_{s2}^{\ast }(2573{)}^{-}+c.c.$
• Global coupled-channel analysis of $e^{+}{e}^{-}\to c\bar{c}$ processes in $\sqrt{s}=3.75-4.7$ GeV
• Cross sections of e+e- --> gamma VV and e+e- --> gamma gamma V
• Partial Wave Analysis of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ and Cross Section Measurement of $e^{+}{e}^{-}\to {\pi }^{\pm }{Z}_c(3900{)}^{\mp }$ from 4.1271 to 4.3583 GeV