Energy Scales in the Local Magnetic Excitation Spectrum of YBa2Cu3O6+y

The wave vector integrated dynamical spin susceptibility (chi) 2D(omega) of YBa 2 Cu 3 O 6+y cuprates is considered. (omega) 2D is calculated in the superconducting state from a renormalized mean field theory of the t tʹ J model, based on the slave boson formulation. Besides the well known "41 meV resonance" a second, much broader peak (ʹhumpʹ) appears in Im (chi) 2D. It is caused by particle hole excitations across the maximum gap (delta) 0 . In contrast to the resonance, which moves to lower energies when the hole filling is reduced from optimal doping, the position of this ʹhumpʹ at ~~2 (delta) 0 stays almost unchanged. The results are in reasonable agreement with inelastic neutronscattering experiments.