Based on multiyear INTEGRAL observations of SS433 , a composite IBIS/ISGRI 18-60 keV orbital light curve is constructed around zero precessional phase \psi _ { pr } = 0 , which corresponds to a maximum separation of the moving emission lines originated in sub-relativistic jets from the source .
It shows a peculiar shape characterized by a significant excess near the orbital phase \phi _ { orb } = 0.25 , which is not seen in the softer 2-10 keV energy band .
Such a shape is likely to be due to a complex asymmetric structure of the funnel in a supercritical accretion disk in SS433 .
The orbital light curve at 40-60 keV demonstrates two almost equal bumps at phases \sim 0.25 and \sim 0.75 , most likely due to nutation effects of the accretion disk .
The change of the off-eclipse 18-60 keV X-ray flux with the precessional phase shows a double-wave form with strong primary maximum at \psi _ { pr } = 0 and weak but significant secondary maximum at \psi _ { pr } = 0.6 .
A weak variability of the 18-60 keV flux in the middle of the orbital eclipse correlated with the disk precessional phase is also observed .
The joint analysis of the broadband ( 18-60 keV ) orbital and precessional light curves obtained by INTEGRAL confirms the presence of a hot extended corona in the central parts of the supercritical accretion disk and constrain the binary mass ratio in SS433 in the range 0.5 \gtrsim q \gtrsim 0.3 , confirming the black hole nature of the compact object .
Orbital and precessional light curves in the hardest X-ray band 40-60 keV , which is free from emission from thermal X-ray jets , are also best fitted by the same geometrical model with hot extended corona at q \sim 0.3 , stressing the conclusions of the modeling of the broad-band X-ray orbital and precessional light curves .