Year: 2026
Type: article
Abstract: 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.
Source: Journal of High Energy Physics
Authors: D. Babusci, P. Beltrame, M. Berlowski, C. Bloise, F. Bossi, P. Branchini, B. Cao, F. Ceradini, P. Ciambrone, L. Cotrozzi, F. Curciarello, E. Czerwiński, G. D’Agostini, R. D’Amico, E. Danè, V. De Leo, E. De Lucia, A. De Santis, P. De Simone, A. Di Domenico, E. Diociaiuti, D. Domenici, A. D’Uffizi, G. Fantini, S. Fiore, A. Gajos, S. Gamrat, P. Gauzzi, S. Giovannella, E. Graziani, F. Ignatov, X. Kang, A. Kupsc, G. Mandaglio, M. Martini, S. Miscetti, P. Moskal, A. Passeri, V. Patera, E. Perez del Rio, L. Punzi, F. Sborzacchi, M. Schioppa, A. Selce, M. Silarski, F. Sirghi, E. P. Solodov, T. Teubner, G. Venanzoni, N. Vestergaard, W. Wiślicki, M. Wolke, E. Zaid
Institutions: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, University of Liverpool, National Centre for Nuclear Research, Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Uppsala University, Roma Tre University, National Agency for New Technologies, Energy and Sustainable Economic Development, Istituto Nazionale di Fisica Nucleare, ENEA Casaccia Research Centre, Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Cosenza, University of Calabria, Jagiellonian University, Istituto Nazionale di Fisica Nucleare, Sezione di Roma I, Sapienza University of Rome, University of Ferrara, ENEA Frascati Research Centre, European Organization for Nuclear Research, China University of Geosciences, University of Messina, Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Marconi University, Scuola Normale Superiore, Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering, Novosibirsk State University, Budker Institute of Nuclear Physics
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Funders: Leverhulme Trust, Narodowe Centrum Nauki
Awards: G4183855946, G4411641907
OpenAlex ID: W7125970916