  Negative superhumps (NSHs) are signals a few percent shorter than the orbital
period of a binary star and are considered to originate from the reverse
precession of the tilted disk. Based on TESS photometry, we find nine new
cataclysmic variable stars (CVs) with NSHs. Three (ASAS J1420, TZ Per, and V392
Hya) of these stars similar to AH Her still have NSHs during dwarf nova
outbursts, and the NSH amplitude varies with the outburst. The variation in the
radius of the accretion disk partially explains this phenomenon. However, it
does not explain the rebound of the NSH amplitude after the peak of the
outburst and the fact that the NSH amplitude of the quiescence is sometimes not
the largest, and it is necessary to combine the disk instability model (DIM)
and add other ingredients. Therefore, we suggest that the variation of NSH
amplitude with outburst can be an essential basis for studying the origin of
NSHs and improving the DIM. The six ( ASASSN-V J1137, ASASSN-V J0611, 2MASS
J0715, LAMOST J0925, ASASSN-17qj, and ZTF18acakuxo) remaining stars have been
poorly studied, and for the first time we determine their orbital periods, NSHs
and Superorbital signal (SOR) periods. The NSH periods and amplitudes of
ASASSN-V J1137 and ASASSN-17qj vary with the SOR, and based on the comparison
of the observations with the theory, we suggest that a single change in tilted
disk angle does not explain the observations of the SOR and that other
ingredients need to be considered as well.
