Consistent picture for resonance-neutron-peak and angle-resolved photoemission spectra in high-T-c superconductors

The spectra observed in angle-resolved photoemission spectroscopy measureme nts are examined together with the resonance peak observed in neutron scatt ering, based on the slave-boson approach to the t-t'-J model. We show that the peak/dip/hump features arise from the scattering of electrons by collec tive spin excitations which, at the same time, give rise to the neutron res onance mode. The doping dependences and the dispersions of the peak/dip/hum p positions are shown to be consistent with experiments. The recently obser ved cos(6 theta) deviation from the pure d wave is also discussed based on the renormalization by spin fluctuations.