Break-up and Coherent Photoproduction of <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math></span> Mesons on the Deuteron

P. Hoffmann-Rothe; M. Krebeck; J. Hey; M. Breuer; G. v. Edel; E. Hourany; M. Rigney; J. Ajaka; G. Anton; J. Arends; G. Berrier-Ronsin; W. Beulertz; G. Blanpied; A. Bock; J.-P. Didelez; K. Helbing; R. Maass; G. Nöldeke; B. Preedom; B. Richie; L. Rosier; B. Saghai; M. Schumacher; F. Smend

doi:10.1103/PhysRevLett.78.4697

Break-up and Coherent Photoproduction of $η$ Mesons on the Deuteron

P. Hoffmann-Rothe, M. Krebeck, J. Hey, M. Breuer, G. v. Edel, E. Hourany, M. Rigney, J. Ajaka, G. Anton, J. Arends, G. Berrier-Ronsin, W. Beulertz, G. Blanpied, A. Bock, J.-P. Didelez, K. Helbing, R. Maass, G. Nöldeke, B. Preedom, B. Richie, L. Rosier, B. Saghai, M. Schumacher, and F. Smend

Phys. Rev. Lett. 78, 4697 – Published 23 June 1997

Abstract

We present new break-up and coherent data for $η$ meson photoproduction on the deuteron, using a deuterium target and tagged bremsstrahlung photons up to 1 GeV. The differential cross sections for the coherent process were measured from threshold to 800 MeV. They are much smaller than those previously reported. The break-up channel provides a direct measurement of the neutron to proton differential cross section ratios. At the $S_{11} (1535)$ resonance peak, $σ_{n} / σ_{p} = 0.68 \pm 0.06$ leading to an isoscalar to isovector amplitude ratio of $A_{s} {/ A}_{υ} = 0.096 \pm 0.02$ .

Received 26 November 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.4697

Authors & Affiliations

P. Hoffmann-Rothe¹, M. Krebeck³, J. Hey², M. Breuer¹, G. v. Edel³, E. Hourany¹, M. Rigney¹, J. Ajaka¹, G. Anton², J. Arends⁸, G. Berrier-Ronsin¹, W. Beulertz², G. Blanpied⁴, A. Bock², J.-P. Didelez¹, K. Helbing², R. Maass³, G. Nöldeke⁷, B. Preedom⁴, B. Richie⁵, L. Rosier¹, B. Saghai⁶, M. Schumacher³, and F. Smend³

¹IN2P3, Institut de Physique Nucléaire, 91406 Orsay, France
²University of Erlangen-Nürnberg, Erwin-Romelstreasse 1, D-91058 Erlangen, Germany
³Zweites Physikalisches Institut, University of Göttingen, Bunsenstrasse 7–9, Göttingen, Germany
⁴Physics Department, University of South Carolina, Columbia, South Carolina 29208
⁵Physics Department, Arizona State University, Tempe, Arizona 85281
⁶CEA/DSM/DAPNIA/SphN, CE-Saclay, 91191 Gif-sur-Yvette, France
⁷Physikalisches Institut, University of Bonn, Nussallee 12, D-53117 Bonn, Germany
⁸Institut für Kernphysik, University of Mainz, Joachim-Becher-Weg 45, D-55099 Mainz, Germany