  We have investigated the electronic states in quasi one dimensional (1D) CuO
chains by microprobe Angle Resolved Photoemission Spectroscopy. We find that
the quasiparticle Fermi surface consists of six disconnected segments,
consistent with recent theoretical calculations that predict the formation of
narrow, elongated Fermi surface pockets for coupled CuO chains. In addition, we
find a strong renormalization effect with a significant kink structure in the
band dispersion. The properties of this latter effect [energy scale (~40 meV),
temperature dependence and behavior with Zn-doping] are identical to those of
the bosonic mode observed in CuO2 planes of high temperature superconductors,
indicating they have a common origin.
