Corrections to Dynamic Scaling for the Lambda Transition in Liquid Helium

Abstract
The noncritical background thermal diffusion is extracted from experimental data and found to be relatively strong. This produces large transient corrections in the critical relaxation rates. The negative amplitude of the slow transient strongly perturbs the entropy relaxation rate. Inclusion of both slow and fast transient yields an excellent fit with Ahler's thermal conductivity data. Light scattering data are also well accounted for.