Collective spin excitations in the singlet-correlated band model: a comparison with resonant inelastic x-ray scattering.

We analyse the spin excitations near the optimal doping of superconducting layered cuprates taking into account both the local and the itinerant spin components self-consistently. The obtained expression allows us to reproduce well the basic features of the resonant inelastic x-ray scattering and neutron scattering data experiments using a reasonable set of tight-binding parameters corresponding to the angle-resolved photoemission spectroscopy data. We also find that the spin excitation branch along the (0,0) - (0,π) symmetry direction in the first Brillouin zone shows a splitting at T < Tc. Possible experiments for verification of that prediction are briefly discussed.