New high-statistics measurement of the π 0 → e + e − γ Dalitz decay at the Mainz Microtron

Physical Review C 2026 Open access

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Authors: S. Prakhov, L. Heijkenskjöld, S. Abt, Patrick Achenbach, P. Adlarson, Farah Noreen Afzal, Zeeshan Ahmed, K. Altangerel, J. R. M. Annand, M. Bashkanov, R. Beck, M. Biroth
+60 more N. S. Borisov, Alessandro Braghieri, W. J. Briscoe, F. Cividini, C. Collicott, S. Costanza, A. Denig, M. Dieterle, А. С. Должиков, E. J. Downie, P. Drexler, S. Fegan, Stephanie J. Gardner, D. Ghosal, D. I. Glazier, I. S. Gorodnov, W. Gradl, M. Günther, G. M. Gurevich, D. Hornidge, Garth M. Huber, A. Käser, V. L. Kashevarov, S. J. D. Kay, M. Korolija, Bernd Krusche, A. B. Lazarev, K. Livingston, S. Lutterer, I. J. D. MacGregor, D. Mark Manley, P. P. Martel, R. Miskimen, M. Mocanu, E. Mornacchi, C. Mullen, A. Neganov, A. Neiser, M. Ostrick, P. B. Otte, D. Paudyal, P. Pedroni, A. Powell, Elisabeth Rickert, T. Rostomyan, V. Sokhoyan, K. Spieker, O. Steffen, I. I. Strakovsky, Th. Strub, I. Supek, M. Thiel, A. Thomas, Yu. A. Usov, S. Wagner, Daniel P. Watts, D. Werthmüller, J. Wettig, M. Wolfes, N. Zachariou
DOI: 10.1103/9tk1-2dxp
Cited by: 0
References: 66

Abstract

The Dalitz decay π 0 → e + e − γ has been measured with the highest statistical accuracy obtained so far in the γ p → π 0 p reaction with the A2 tagged-photon facility at the Mainz Microtron, MAMI. The value of the slope parameter for the π 0 electromagnetic transition form factor, a π = 0.0315 ± 0 . 0026 stat ± 0 . 0010 syst , is obtained from the analysis of 2.4 × 10 6 π 0 → e + e − γ observed decays. Within experimental uncertainties, it is in agreement with existing measurements and theoretical calculations, with its own uncertainty being smaller than previous results based on the analysis of π 0 → e + e − γ decays.

Fields of Study & Subjects

Quantum Chromodynamics and Particle Interactions Particle physics theoretical and experimental studies Nuclear physics research studies

Publication details

Journal / source
Physical Review C
Volume
113
Issue
6
Publication date
4 May 2026
Language
EN