  We carried out a simulation of heavy ion collision using a time-dependent
density functional theory. We call it the canonical-basis time-dependent
Hartree-Fock-Bogoliubov theory (Cb-TDHFB) which can describe nuclear dynamics
in three-dimensional coordinate space, treating nuclear pairing correlation. We
simulate 20O+20O collision using the Cb-TDHFB with a contact-type pairing
functional, and show the behavior of gap energy which is decreasing and
vibrating while colliding.
