Coupling of zero sound to the real squashing mode in rotating B3

Rotation of superfluid B3 in an magnetic field enhances the coupling of the nonzero mJ substrates of the real squashing collective mode to the zero sound, and the fivefold line splitting becomes observable even when H is parallel to and to the direction of sound propagation. Equilibrium vortex lattices and vortex-free states can be distinguished by their characteristic absorption spectra. The dependence of the sound attenuation on the angular velocity in magnetic fields up to 32 mT is reported; the data are qualitatively compared with theory.