Observation of a Threshold Enhancement in the π 0π 0 Mass Spectrum in ψ(3686) rightarrow π 0 π 0 J/ψ Decays

Original title: Observation of a Threshold Enhancement in the π⁰π⁰ Mass Spectrum in ψ(3686) → π⁰π⁰J/ψ Decays

Using a data sample of (2712.4 pm14.4)x 10 6 ψ(3686) events collected with the BESIII detector, we report a high-precision study of the π 0 π 0 mass spectrum from ψ(3686) rightarrowπ 0 π 0 J/ψ decays.

By BESIII Collaboration, Ablikim, Achasov +197Oct 9, 2026

Score████░░░░░░4.2

Key numbers

0.3 GeV

Caveats

Preprint; not yet peer reviewed.

VerdictWorth a reader's time today.

Read the original PDF

Abstract

Using a data sample of (2712.4±14.4)× 10⁶ $ψ(3686)$ events collected with the BESIII detector, we report a high-precision study of the π⁰π⁰ mass spectrum from ψ(3686)→π⁰π⁰J/ψ decays. The enhancement previously observed near the $ππ$ mass threshold in the π⁺π⁻ channel is confirmed, with a statistical significance exceeding 10$σ$. A fit with a Breit-Wigner function yields a mass of M = 274.3± 2.1_rm stat.±0.6_rm syst.~rm MeV/c² and a width of Γ= 17.1± 1.5_rm stat.±0.5_rm syst.~rm MeV, consistent with those from the π⁺π⁻ channel. By including final-state interactions, we analyze the data using both chiral perturbation theory (ChPT) and QCD multipole expansion (QCDME). While the ChPT model describes the higher-mass region above 0.3 GeV/c² well, it fails to reproduce the significant threshold enhancement. In contrast, the QCDME model, which incorporates the S- and D-wave admixture structure of $ψ(3686)$, provides a better description of the full π⁰π⁰ mass spectrum.

BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, M. S. Anderson, Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, M. Barbagiovanni, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, D. Cabiati, H. Cai, et al.

The editor's rubric

Heuristic review

Dimension	Level	Weight	What that level means
Leverage	███░░ 3	18%	A method or resource many groups across the field will adopt within a year.
Magnitude	███░░ 3	20%	Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.
Evidence	███░░ 3	22%	Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.
Novelty	███░░ 3	22%	A genuinely new approach to an open problem.
Trajectory	██░░░ 2	10%	Some room to improve with obvious engineering.
Stakes	██░░░ 2	8%	Benefits a professional community (practitioners, clinicians, engineers).

Editor’s rationale

Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: method (we report); gains (outperforms); novelty (discovery); verification (error bars, independent replication).

How the score was computed

rank-2026-10-07

Score████░░░░░░4.2

Score = 10 × (75% × adjusted merit / 10 + 15% × attention + 10% × freshness)

Merit: 5.6 / 10; Weighted rubric, evidence-gated.
Adjusted merit: 4.7 / 10; Shrunk toward the desk prior by editor confidence (40%).
Attention: 0%; Citations, upvotes, points, mentions.
Freshness: 74%; Half-life decay since publication.

Citations0 (reference 20, via semantic-scholar, Oct 12, 2026, 07:25 UTC)

The record

Reviewed by heuristic-v6 on Oct 12, 2026, 07:25 UTC. Paper type: method.
Categories: hep-ex
TOP, No.5 in the Physics edition of October 12, 2026.