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arxiv: 2604.13652 · v1 · submitted 2026-04-15 · ✦ hep-ex

Precision Studies of the η_c decay at BESIII

Yijia Zeng (on behalf of BESIII Collaboration) This is my paper

Pith reviewed 2026-05-10 12:32 UTC · model grok-4.3

classification ✦ hep-ex
keywords eta_c decaysBESIIIcharmoniumJ/ψ radiative transitionshadronic decaystwo-photon decay
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The pith

BESIII measures η_c decay properties with high precision using world-largest J/ψ samples.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

BESIII has collected the world's largest samples of J/ψ and ψ(3686) decays at the BEPCII collider. These samples allow production of large numbers of η_c mesons through radiative transitions like J/ψ to gamma η_c. The paper reviews precision measurements of the η_c to gamma gamma decay and several hadronic decay modes. Such studies test models of the strong force in the charm quark sector by examining the structure of this charmonium state.

Core claim

BESIII has performed precision studies of the η_c decays, including the production via J/ψ→γη_c, the two-photon decay η_c→γγ, and several hadronic decays, based on the large data sets collected.

What carries the argument

Radiative transitions from J/ψ to γη_c that produce η_c samples for decay studies.

Load-bearing premise

The analyses assume that systematic uncertainties from background modeling and efficiency corrections are well controlled and do not bias the compiled results.

What would settle it

An independent measurement finding a branching ratio for η_c→γγ differing by more than the quoted uncertainties from the BESIII value.

read the original abstract

The lowest lying charmonium system $\eta_c$ has been observed for more than four decades. Studies of its production and decay properties provide an unique platform to investigate the inner structure of charmonium systems, hence improve our understanding of strong interaction in the charm sector. BESIII detector at the $e^+e^-$ BEPCII collider has already collected the world largest $J/\psi$ and $\psi(3686)$ data sets, based on which massive $\eta_c$ samples are produced via radiative transitions. This paper reviews recent precision studies of the $\eta_c$ decays at BESIII, including $J/\psi\to\gamma\eta_c$, $\eta_c\to\gamma\gamma$, and several $\eta_c$ hadronic decays.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. This manuscript is a review summarizing recent precision studies of the η_c charmonium decays performed by the BESIII experiment. It covers the radiative production channel J/ψ → γ η_c, the two-photon decay η_c → γγ, and multiple hadronic decay modes, drawing on the world's largest J/ψ and ψ(3686) data samples collected at the BEPCII collider.

Significance. If the compiled results accurately reflect the underlying measurements, the review provides a useful consolidation of current experimental knowledge on η_c properties, which serves as an important benchmark for theoretical models of charmonium structure and QCD in the charm sector. The paper correctly emphasizes the advantage of BESIII's large data sets for enabling high-statistics studies.

major comments (1)
  1. [Abstract] The central claim that BESIII has performed 'precision studies' (Abstract) rests entirely on the systematic uncertainties and efficiency corrections reported in the cited original analyses; the review does not re-derive or cross-check background modeling, radiative transition rates, or efficiency corrections, leaving open the possibility that unaccounted biases could affect the quoted precisions.
minor comments (2)
  1. [Abstract] The abstract lists the topics covered but does not indicate the number of hadronic modes reviewed or the time period of the included results; adding this would improve clarity for readers.
  2. A summary table compiling the key measured quantities (branching fractions, widths, etc.) with references to the original papers would enhance the utility of the review.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the positive assessment of our manuscript as a useful consolidation of experimental knowledge on the η_c and for the recommendation of minor revision. We address the single major comment point by point below.

read point-by-point responses

  1. Referee: [Abstract] The central claim that BESIII has performed 'precision studies' (Abstract) rests entirely on the systematic uncertainties and efficiency corrections reported in the cited original analyses; the review does not re-derive or cross-check background modeling, radiative transition rates, or efficiency corrections, leaving open the possibility that unaccounted biases could affect the quoted precisions.

    Authors: This manuscript is a review article whose purpose is to summarize and highlight the precision measurements of η_c production and decays performed by the BESIII collaboration. The quoted results, including all systematic uncertainties, background modeling, radiative transition rates, and efficiency corrections, are taken directly from the peer-reviewed original publications cited throughout the text. As is standard for review papers, we do not re-derive or independently cross-check these quantities; instead, we refer readers to the detailed analyses in the cited works for those technical aspects. The review emphasizes the experimental advantages provided by BESIII's world-largest J/ψ and ψ(3686) data samples that enabled the high-statistics studies reported in those papers. We therefore maintain that the description of these as 'precision studies' is accurate and appropriately sourced. revision: no

Circularity Check

0 steps flagged

Review compiles published BESIII results with no derivation chain or circular reductions

full rationale

The paper is explicitly a review summarizing existing precision measurements of η_c decays (J/ψ→γη_c, η_c→γγ, hadronic modes) from prior BESIII analyses. No new derivations, predictions, first-principles calculations, or fittings are performed. The abstract states it 'reviews recent precision studies' based on collected data sets, with no equations or model reductions presented. Self-citations to BESIII collaboration papers are normal for an internal review and do not create load-bearing circularity because the underlying results are independently published experimental measurements. No steps reduce by construction to inputs, fitted parameters, or self-defined quantities.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is a review paper summarizing experimental results from BESIII; it introduces no new free parameters, axioms, or invented entities.

pith-pipeline@v0.9.0 · 5418 in / 985 out tokens · 38596 ms · 2026-05-10T12:32:38.034380+00:00 · methodology

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Reference graph

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