  Accretion disks around black hole, neutron star, and white dwarf systems are
thought to sometimes tilt, retrogradely precess, and produce hump-shaped
modulations in light curves that have a period shorter than the orbital period.
Although artificially rotating numerically simulated accretion disks out of the
orbital plane and around the line of nodes generates these short-period
superhumps and retrograde precession of the disk, no numerical code to date has
been shown to produce a disk tilt naturally. In this work, we report the first
naturally tilted disk in non-magnetic Cataclysmic Variables (CVs) using 3D
Smoothed Particle Hydrodynamics (SPH). Our simulations show that after many
hundreds of orbital periods, the disk has tilted on its own and this disk tilt
is without the aid of radiation sources or magnetic fields. As the system
orbits, the accretion stream strikes the bright spot (which is on the rim of
the tilted disk) and flows over and under the disk on different flow paths.
These different flow paths suggest the lift force as a source to disk tilt. Our
results confirm the disk shape, disk structure, and negative superhump period
and support the source to disk tilt, source to retrograde precession, and
location associated with X-ray and He II emission from the disk as suggested in
previous works. Our results identify the fundamental negative superhump
frequency as indicator of disk tilt around the line of nodes.
