Measurement of the omega -> pi(0)e(+)e(-) and eta -> e(+)e(-)gamma Dalitz decays with the A2 setup at the Mainz Microtron

P. Adlarson, F. Afzal, P. Aguar-Bartolome, Z. Ahmed, J. R. M. Annand, H. J. Arends, K. Bantawa, R. Beck, H. Berghaeuser, M. Biroth, N. S. Borisov, A. Braghieri, W. J. Briscoe, S. Cherepnya, F. Cividini, C. Collicott, S. Costanza, I. V. Danilkin, A. Denig, M. DieterleE. J. Downie, P. Drexler, M. I. Ferretti Bondy, L. V. Fil'kov, S. Gardner, S. Garni, D. I. Glazier, D. Glowa, W. Gradl, G. M. Gurevich, D. J. Hamilton, D. Hornidge, G. M. Huber, T. C. Jude, A. Kaeser, V. L. Kashevarov, S. Kay, I. Keshelashvili, R. Kondratiev, M. Korolija, B. Krusche, A. Lazarev, J. Linturi, V. Lisin, K. Livingston, I. J. D. MacGregor, C. Mullen, M. H. Sikora, D. P. Watts, L. A. Zana, A2 Collaboration MAMI

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Abstract

The Dalitz decays eta -> e(+)e(-)gamma and omega -> pi(0)e(+)e(-) have been measured in the gamma p -> eta p and gamma p -> omega p reactions, respectively, with the A2 tagged-photon facility at the Mainz Microtron. The value obtained for the slope parameter of the electromagnetic transition form factor of eta, Lambda(-2)(eta) = (1.97 +/- 0.11(tot)) GeV-2, is in good agreement with previous measurements of the eta -> e(+)e(-)gamma and eta ->mu(+)mu(-)gamma decays. The uncertainty obtained in the value of Lambda(-2)(eta) is lower than in previous results based on the eta -> e(+)e(-)gamma decay. The value obtained for the omega slope parameter Lambda(0-2)(omega pi) = (1.99 +/- 0.21(tot)) GeV-2, is somewhat lower than previous measurements based on omega -> pi(0)mu(+)mu(-), but the results for the omega transition form factor are in better agreement with theoretical calculations, compared to earlier experiments.

Original languageEnglish
Article number035208
Number of pages18
JournalPhysical Review C
Volume95
Issue number3
DOIs
Publication statusPublished - 22 Mar 2017

Keywords

  • TRANSITION FORM-FACTOR
  • TAGGED PHOTON SPECTROMETER
  • VECTOR-MESONS
  • LIGHT VECTOR
  • MAMI-B
  • SCATTERING
  • TAPS

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