We combine neutron scattering (INS) and NMR/NQR nuclear spin lattice
relaxation rate data to deduce the existence of a new contribution to the
magnetic response (dynamic susceptibility) in cuprate superconductors. This
contribution, which has yet to be observed with INS, is shown to embody the
magnetic pseudogap effects. As such, it explains the long-standing puzzle of
pseudogap effects missing from cuprate INS data, dominated by stripe
fluctuations, for the dynamic susceptibility at low energies. For
La_(1.86)Sr_(0.14)CuO_(4) and YBa_(2)Ba_(3)O_(6.5), the new term is the chief
contributor to nuclear spin lattice relaxation at T >> T_(c).Comment: 11 pages, 2 figures. Augmented version to be published in Physical
Review
