Speaker
Description
The interaction between an eta meson and a nucleus provides the in-medium modification of the eta meson and/or a chiral partner candidate of the nucleon $N(1535)1/2^-$, to which the eta meson and nucleon couples. We have studied such an interaction for the lightest nucleus, deuteron, from the measurement of cross sections for coherent neutral-pion and eta-meson photoproduction on the deuteron. We have found a narrow resonance-like bump in the eta-deuteron subsystem at the vicinity of the threshold, suggesting strong eta-deuteron attraction. The sharp backward-peaking angular dependence of deuteron emission, predicted by the existing theoretical calculations, does not appear. We discuss the possibilities of using coherent neutral-pion and eta-meson photoproduction on a nucleus to study the eta-nuclear interaction.
