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Main Authors: Peng, Tian-Cai, Bai, Zi-Yue, Wang, Jun-Zhang, Liu, Xiang
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.03705
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author Peng, Tian-Cai
Bai, Zi-Yue
Wang, Jun-Zhang
Liu, Xiang
author_facet Peng, Tian-Cai
Bai, Zi-Yue
Wang, Jun-Zhang
Liu, Xiang
contents Recently, the BESIII collaboration performed a precise measurement of the $e^+e^-\to ηJ/ψ$ cross section. It is puzzling that the resonance parameters of the reported $Y(4230)$ show a substantial divergence from the previously measured results in both the open-charmed and hidden-charmed decay channels, and the line shape asymmetry of the data approaching 4.2 GeV also suggests that it might be difficult to characterize the details of the structure around 4.2 GeV by a single resonance. This has motivated our great curiosity about how the charmonium states are distributed in the measured energy range and how they shape the puzzling data of the $e^+e^-\to ηJ/ψ$ cross section. In this work, we use five theoretically constructed charmonia in the range of $4.0\rm{-}4.5$ $\text{GeV}$, i.e., $ψ(4040)$, $ψ(4160)$, $ψ(4220)$, $ψ(4380)$, and $ψ(4415)$, to apply a combined fit to the data, in which their calculated decay ratios into $ηJ/ψ$ via hadronic loop mechanism are taken as input. The fit results can reproduce the measured cross section data well, especially for the subtle line shape around 4.2 GeV, showing that the structure around 4.2 GeV is possible from the contribution of both $ψ(4160)$ and $ψ(4220)$.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03705
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle How higher charmonia shape the puzzling data of the $e^+e^-\to ηJ/ψ$ cross section
Peng, Tian-Cai
Bai, Zi-Yue
Wang, Jun-Zhang
Liu, Xiang
High Energy Physics - Phenomenology
High Energy Physics - Experiment
Recently, the BESIII collaboration performed a precise measurement of the $e^+e^-\to ηJ/ψ$ cross section. It is puzzling that the resonance parameters of the reported $Y(4230)$ show a substantial divergence from the previously measured results in both the open-charmed and hidden-charmed decay channels, and the line shape asymmetry of the data approaching 4.2 GeV also suggests that it might be difficult to characterize the details of the structure around 4.2 GeV by a single resonance. This has motivated our great curiosity about how the charmonium states are distributed in the measured energy range and how they shape the puzzling data of the $e^+e^-\to ηJ/ψ$ cross section. In this work, we use five theoretically constructed charmonia in the range of $4.0\rm{-}4.5$ $\text{GeV}$, i.e., $ψ(4040)$, $ψ(4160)$, $ψ(4220)$, $ψ(4380)$, and $ψ(4415)$, to apply a combined fit to the data, in which their calculated decay ratios into $ηJ/ψ$ via hadronic loop mechanism are taken as input. The fit results can reproduce the measured cross section data well, especially for the subtle line shape around 4.2 GeV, showing that the structure around 4.2 GeV is possible from the contribution of both $ψ(4160)$ and $ψ(4220)$.
title How higher charmonia shape the puzzling data of the $e^+e^-\to ηJ/ψ$ cross section
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2403.03705