Publications (6)5.5 Total impact
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Article: Photoproduction of on protons and the (1700)D33 -resonance
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ABSTRACT: Total and differential cross-sections for the reaction gp®p0hp\ensuremath \gamma p\rightarrow\pi^0\eta p have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range Eg = 0.95-1.4\ensuremath E_{\gamma} = 0.95\mbox{--}1.4 GeV the reaction is dominated by the excitation and sequential decay of the D(1700)D33\ensuremath \Delta(1700)D_{33} -resonance. Angular distributions measured with high statistics allow us to determine the ratio of hadronic decay widths GhD/GpS11\ensuremath \Gamma_{\eta\Delta}/\Gamma_{\pi S_{11}} and the ratio of the helicity amplitudes A3/2/A1/2\ensuremath A_{3/2}/A_{1/2} for this resonance.European Physical Journal A 04/2012; 42(2):141-149. · 2.19 Impact Factor -
Article: Erratum: Experimental study of the γp→ηp reaction with the Crystal Ball detector at the Mainz Microtron (MAMI-C) [Phys. Rev. C 82, 035208 (2010)]
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ABSTRACT: Here we correct a factor of 2 missed in one of figures and the corresponding sentence in the text. It does not change any conclusions.Physical Review C 07/2011; 84(2):29901. · 3.31 Impact Factor -
Article: First measurement of the circular beam asymmetry in the gamma p --> pi0 eta p reaction
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ABSTRACT: The circular photon asymmetry for pi0 eta photoproduction on the proton was measured for the first time at the tagged photon facility of the MAMI C accelerator using the Crystal Ball/TAPS photon spectrometer. The experimental results are interpreted within a phenomenological isobar model that confirms the dominant role of the Delta(1700)D33 resonance. The measured asymmetry allows us to identify small contributions from positive-parity resonances via interference terms with the dominant D33 amplitude. Comment: 11 pages, 3 figures, submitted to Phys.Lett. B09/2010; -
Article: Study of the gp-->etap reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C)
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ABSTRACT: The gp-->etap reaction has been measured with the Crystal Ball and TAPS multiphoton spectrometers in the energy range from the production threshold of 707 MeV to 1.4 GeV (1.49 =< W >= 1.87 GeV). Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz Microtron MAMI-C and momentum analyzed by the Glasgow Tagging Spectrometer were used for the eta-meson production. Our accumulation of 3.8 x 10^6 gp-->etap-->3pi0p-->6gp events allows a detailed study of the reaction dynamics. The gp-->etap differential cross sections were determined for 120 energy bins and the full range of the production angles. Our data show a dip near W = 1680 MeV in the total cross section caused by a substantial dip in eta production at forward angles. The data are compared to predictions of previous SAID and MAID partial-wave analyses and to thelatest SAID and MAID fits that have included our data. Comment: 15 pages, 12 figures07/2010; -
Article: Photoproduction of pi^0 eta on protons and the Delta(1700)D_{33} resonance
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ABSTRACT: Total and differential cross sections for the reaction gamma p -> pi^o eta p have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range E_gamma=0.95-1.4 GeV the reaction is dominated by the excitation and sequential decay of the Delta(1700)D33 resonance. Angular distributions measured with high statistics allow us to determine the ratio of hadronic decay widths \Gamma_{\eta \Delta}/\Gamma_{\pi S11} and the ratio of the helicity amplitudes A_{3/2}/A_{1/2} for this resonance. Comment: 9 pages, 11 figures01/2009; -
Article: Measurement of the Slope Parameter $\alpha$ for the $\eta\to 3\pi^0$ decay with the Crystal Ball detector at the Mainz Microtron (MAMI-C)
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ABSTRACT: The dynamics of the $\eta\to 3\pi^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $\eta$-meson production. The analysis of $3 \times 10^6$ $\gamma p \to \eta p \to 3\pi^0 p \to 6\gamma p$ events yields the value $\alpha=-0.032\pm0.003$ for the $\eta\to 3\pi^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $\pi^0\pi^0$ invariant-mass spectrum was investigated for the occurrence of a cusplike structure in the vicinity of the $\pi^+\pi^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.12/2008;
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Institutions
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2008–2010
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Johannes Gutenberg-Universität Mainz
- Institute of Nuclear Physics
Mainz, Rhineland-Palatinate, Germany
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