Corrections to Higgs mode masses in superfluid He 3 from acoustic spectroscopy

Superfluid He3 has a rich spectrum of collective modes with both massive and massless excitations. The masses of these modes can be precisely measured using acoustic spectroscopy and fit to theoretical models. Prior comparisons of the experimental results with theory did not include strong-coupling effects beyond the weak-coupling-plus BCS model, so-called nontrivial strong-coupling corrections. In this paper we utilize recent strong-coupling calculations to determine the Higgs masses and find consistency between experiments that relate them to a subdominant f-wave pairing strength.