Determination of the η-transition form factor in the γp→pη→pγe+e− reaction (CROSBI ID 174906)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Berghäuser, H. ; Metag, V. ; Starostin, A. ; Aguar Bartolomé, P. ; Akasoy, L.K. ; Annand, J.R.M. ; Arends, H.J. ; Bantawa, K. ; Beck, R. ; Bekrenev, V. ; Braghieri, A. ; Branford, D. ; Briscoe, W.J. ; Brudvik, J. ; Cherepnya, S. ; Demissie, B.T. ; Downie, E.J. ; Drexler, P. ; Dieterle, M. ; Fil’kov, L.V. ; Fix, A. ; Glazier, D.I. ; Heid, E. ; Hornidge, D. ; Jahn, O. ; Jude, T.C. ; Kashevarov, V.L. ; Knežević, Andrea ; Kondratiev, R. ; Korolija, Milorad ; Kotulla, M. ; Koulbardis, A. ; Kruglov, S. ; Krusche, B. ; Lemmer, B. ; Lisin, V. ; Livingston, K. ; MacGregor, I.J.D. ; Maghrbi, Y. ; Manley, D.M. ; Martinez-Fabregate, M. ; McGeorge, J.C. ; McNicoll, E.F. ; Mekterović, Darko ; Mićanović, Saša ; Mushkarenkov, A. ; Nefkens, B.M.K. ; Nikolaev, A. ; Novotny, R. ; Ostrick, M. ; Owens, R.O. ; Pedroni, P. ; Pheron, F. ; Polonski, A. ; Prakhov, S.N. ; Robinson, J. ; Rosner, G. ; Rostomyan, T. ; Schumann, S. ; Sober, D. I. ; Suarez, I.M. ; Supek, Ivan ; Tarbert, C.M. ; Thiel, M. ; Thomas, A. ; Unverzagt, M. ; Watts, D.P. ; Werthmüller, D. ; Zamboni, Ivana ; Zehr, F.
engleski
Determination of the η-transition form factor in the γp→pη→pγe+e− reaction
The Dalitz decay η→γe+e− has been measured using the combined Crystal Ball and TAPS photon detector setup at the electron accelerator MAMI-C. Compared to the most recent transition form-factor measurement in the e+e− channel, statistics have been improved by one order of magnitude. The e+e− invariant mass distribution shows a deviation from the QED prediction for a point-like particle, which can be described by a form-factor. Using the usual monopole transition form-factor parameterization, F(m^2)=(1−m^2/Λ^2)^−1, a value of Λ^−2=(1.92±0.35(stat)±0.13(syst)) GeV^−2 has been determined. This value is in good agreement with a recent measurement of the η Dalitz decay in the μ+μ− channel and with recent form-factor calculations. An improved value of the branching ratio BR(η→γe+e−)=(6.6±0.4(stat)±0.4(syst))•10^−3 has been determined.
Meson decays ; Transition form factor
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Podaci o izdanju
701 (5)
2011.
562-567
objavljeno
0370-2693
1873-2445
10.1016/j.physletb.2011.06.069
