  We study the polar quasinormal modes of spontaneously scalarized black holes
in Einstein-Gauss-Bonnet theory. In previous works we showed that a set of
nodeless solutions of the fundamental branch of the model studied in [1] are
stable under both radial [2] and axial perturbations [3]. Here we calculate the
polar quasinormal modes and show that this set of solutions is stable against
the polar perturbations as well. Thus for a certain region of the parameter
space the scalarized black holes are potentially stable physically interesting
objects. The spectrum of the polar quasinormal modes differs both
quantitatively and qualitatively from the Schwarzschild one which offers the
possibility to test the Gauss-Bonnet theory via the future gravitational wave
observations.
