Abstract
To decide whether magnetic fluctuations are present in the high-temperature superconductor YBa2Cu3O7, we carried out a neutron scattering experiment, using 3-dimensional polarization analysis at temperatures between 70 K and 300 K. The total magnetic intensity within energy windows - Ω < ℏω < Ω for Ω = 12 meV and 25 meV is vanishingly small. Very severe upper bounds for the total magnetic intensity could be established, making magnetic couplings as a source for superconductivity in YBa2Cu3O7 highly unlikely.