  We study dynamic processes through which the scalar hair of black holes is
generated or detached in a theory with a scalar field non-minimally coupled to
Gauss-Bonnet and Ricci scalar invariants. We concentrate on the nonlinear
temporal evolution of a far-from-equilibrium gravitational system. In our
simulations, we choose the initial spacetime to be either a bald Schwarzschild
or a scalarized spherically symmetric black hole. Succeeding continuous
accretion of the scalar field onto the original black hole, the final fate of
the system displays intriguing features, which depend on the initial
configurations, strengths of the perturbation, and specific metric parameters.
In addition to the scalarization process through which the bald black hole
addresses scalar hair, we observe the dynamical descalarization, which removes
scalar hair from an original hairy hole after continuous scalar field
accretion. We examine the temporal evolution of the scalar field, the metrics,
and the Misner-Sharp mass of the spacetime and exhibit rich phase structures
through nonlinear dynamical processes.
