  We investigate the shot cutoff timescale evolutions during different spectral
states in the black hole binary Cygnus X-1 with the recently proposed w
spectral analysis technique. For low energy shots, their cutoff timescale
decreases from the low state to intermediate state, and to high state
monotonically. However in the high energy range, where shots are believed to be
reprocessed in the hot corona, timescales are almost the same for different
spectral states. A linear correlation is found between the energy spectrum
photon index and the shot cutoff timescale at low energies. Both narrow and
broad iron Kalpha lines are distinguished from timing analysis, providing
dynamical evidence that broad and narrow iron lines originate respectively at
small and large radii of the accretion disk. Possible mechanisms for state
transitions and accretion flow geometry in accreting stellar mass black holes
are discussed.
