https://doi.org/10.1140/epja/i2015-15006-3
Regular Article - Experimental Physics
Photoproduction of ω mesons off protons and neutrons
1
II. Physikalisches Institut, Universität Gießen, Gießen, Germany
2
Helmholtz-Institut für Strahlen- u. Kernphysik, Universität Bonn, Bonn, Germany
3
Physikalisches Institut, Universität Bonn, Bonn, Germany
4
Department Physik, Universität Basel, Basel, Switzerland
5
Kernfysisch Versneller Institut, University of Groningen, Groningen, The Netherlands
6
Department of Physics, Florida State University, Tallahassee, FL, USA
7
Petersburg Nuclear Physics Institute, Gatchina, Russia
8
Institut für Theoretische Physik, Universität Gießen, Gießen, Germany
* e-mail: Frida.Hjelm@exp2.physik.uni-giessen.de
Received:
8
July
2014
Revised:
19
December
2014
Accepted:
14
January
2015
Published online:
27
January
2015
ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π0 γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ≈ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E γ < 1.6 GeV. For higher incident beam energies this factor goes down to ≈ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements.
© SIF, Springer-Verlag Berlin Heidelberg, 2015