Measurement of η → π0γγ branching fraction with the KLOE detector
A bstract We present a measurement of the doubly radiative decay η → π 0 γγ based on a sample of 82 million η mesons produced in the e + e − → ϕ → ηγ process at the Frascati ϕ -factory DAΦNE. From the data analysis, 1246 ± 133 signal events were observed. By normalising the signal to the well-known η → 3 π 0 decay the branching fraction $$\mathcal{B}(\eta \to {\pi }^{0}\gamma \gamma )$$ is measured to be (0 . 98 ± 0 . 11 stat ± 0 . 14 syst ) × 10 − 4 . This result agrees with a preliminary KLOE measurement, but is a factor of two smaller than the current world average. Results for d Γ( η → π 0 γγ ) /dM 2 ( γγ ) are also presented and compared with the latest theoretical predictions.
Authors
- G. Venanzoni (ORCID: https://orcid.org/0000-0002-3525-476X)
- M. Wolke
- C. Bloise (ORCID: https://orcid.org/0000-0002-1563-8969)
- A. D'Uffizi
- A. Gajos (ORCID: https://orcid.org/0000-0002-7536-6459)
- A. De Santis (ORCID: https://orcid.org/0000-0002-8613-8128)
- S. Fiore (ORCID: https://orcid.org/0000-0001-9933-3961)
- M. Berłowski
- M. Silarski (ORCID: https://orcid.org/0000-0003-2206-0963)
- K. Dunne (ORCID: https://orcid.org/0000-0003-2626-2247)
- Randy S. D’Amico (ORCID: https://orcid.org/0000-0002-3047-945X)
- F. Curciarello
- P. Beltrame (ORCID: https://orcid.org/0000-0001-9523-6128)
- Filippo Ceradini
- Danilo Babusci
- F. Bossi
- Erika De Lucia
- Bo Cao
- Lorenzo Punzi
- Simona Giovannella
- S. Gamrat
- P. De Simone
- G. Mandaglio
- A. Di Domenico
- X. Kang
- G. D’Agostini
- G. Fantini
- W. Wiślicki
- A. Kupsc
- P. Gauzzi
- E. Perez del Rio
- S. Miscetti
- V. Patera
- E. P. Solodov
- E. Zaid
- M. Schioppa
- N. Vestergaard
- T. Teubner
- A. Selce
- A. Passeri
- P. Moskal
- P. Ciambrone
- V. De Leo
- L. Cotrozzi
- P. Branchini
- D. Domenici
- F. Ignatov
- F. Sirghi
- M. Martini
- E. Czerwiński
- E. Graziani
- F. Sborzacchi
Institutions
- National Agency for New Technologies, Energy and Sustainable Economic Development (IT)
- Roma Tre University (IT)
- Uppsala University (SE)
- Jagiellonian University (PL)
- University of Liverpool (GB)
- Scuola Normale Superiore (IT)
- Novosibirsk State University (RU)
- University of Ferrara (IT)
- Marconi University (IT)
- China University of Geosciences (CN)
- Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre (IT)
- Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (RO)
- National Centre for Nuclear Research (PL)
- Azienda Ospedaliera di Cosenza (IT)
- National Interuniversity Consortium for the Physical Sciences of Matter (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Catania (IT)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Roma I (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa (IT)
- ENEA Frascati Research Centre
- Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Cosenza
- University of Calabria (IT)
- Budker Institute of Nuclear Physics (RU)
- European Organization for Nuclear Research (CH)
- Sapienza University of Rome (IT)
Publication Details
- Journal
- Journal of High Energy Physics
- Published
- 2026-01-15
- DOI
- https://doi.org/10.1007/jhep01(2026)091
- Primary Topic
- Particle physics theoretical and experimental studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00