Photoproduction of omega mesons on nuclei near the production threshold

The photoproduction of \( \omega\) mesons on LH2 , C and Nb has been measured for incident photon energies from 900 to 1300MeV using the CB/TAPS detector at ELSA. The \( \omega\) lineshape does not show any significant difference between the LH2 and the Nb targets. The experiment was motivated by transport calculations that predicted a sensitivity of the \( \omega\) lineshape to in-medium modifications near the production threshold on a free nucleon of \(\ensuremath{E_{\gamma}^{lab}=1109}\) MeV. A comparison with recent calculations is given.