On the linewidth/K vs. mass ratio relation for SU Ursae Majoris stars and the removal of the inner disk

We have calibrated the linewidth/K vs. mass ratio relation for SU UMa stars using the "superhump" mass ratio derived from the tidal resonance model. W e find that the relation by Jurcevic et al. (1994) is valid for dwarf novae above the period gap but not for SU UMa stars. Under the hypothesis of Kep lerian disks, our results are compatible with the removal of the inner disk in SU UMa stars with extreme cycle lengths. The large long-term FWHM varia bility observed in WZ Sge suggests that the fraction of mass removed from t he disk is variable and possibly a function of the supercycle phase. We show a new empirical formula between mass ratio and FWHM/K. It fits the mass ratio of dwarf novae above and below the period gap with a mean relati ve dispersion of 16% and 26%, respectively, except for the post-period mini mum candidates EG Cnc and WZ Sge.