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2008
Journal Article
Titel
New results on the Roper resonance and the Rho-11 partial wave
Abstract
Properties of the Roper resonance, the first scalar excitation of the nucleon, are determined. Pole positions and residues of the Rho-11 partial wave are studied in a combined analysis of pion- and photoinduced reactions. We find the Roper pole at [(1371 +/-7) - jota(92 +/-10)] MeV and an elasticity of0.61 +/- 0.03. The largest decay coupling is found for the Eta sigma (sigma = (pi pi)-Sigma-wave). The analysis is based on new data on gamma rho -> rho pi(0)pi(0) for photons in the energy range from the two-pion threshold to 820 MeV from TAPS at Mainz and from 0.4 to 1.3 GeV from Crystal Barrel at Bonn and includes further data from other experiments. The partial wave analysis excludes the possibility that the Roper resonance is split into two states with different partial decay widths.
Author(s)
Sarantsev, A.V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany / Petersburg Nuclear Physics Institute, Gatchina, Russia
Kotulla, M.
Physikalisches Institut, Universität Basel, Switzerland / II. Physikalisches Institut, Universität Gießen, Germany
Anisovich, A.V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany / Petersburg Nuclear Physics Institute, Gatchina, Russia
Beck, R.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany / Johannes Gutenberg Universität Mainz, Institut für Kernphysik, Mainz, Germany
Crede, V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany / Department of Physics, Florida State University, Tallahassee, FL, USA
Foesel, A.
Helmholtz-Institut für Strahlen- u. Kernphysik Universität Bonn, Germany / Physikalisches Institut, Universität Erlangen, Germany
Kopf, B.
Institut für Kern- und Teilchenphysik TU Dresden, Germany / Physikalisches Institut, Universität Bochum, Germany
Messchendorp, J.G.
KVI, University of Groningen, The Netherlands / II. Physikalisches Institut, Universität Gießen, Germany