  Einstein-scalar-Gauss-Bonnet gravity has recently been known to exhibit
spontaneous scalarization. In the presence of the Gauss-Bonnet term the no-hair
theorem can be evaded and novel black hole solutions with non-trivial scalar
fields have been found besides the general relativistic solutions. In this
paper, we aim to investigate the possibility of observationally testing
Einstein-scalar-Gauss-Bonnet gravity using thin accretion disk properties
around such scalarized black holes. Using the Novikov-Thorne model, we
numerically calculate the electromagnetic flux, temperature distribution,
emission spectrum, innermost stable circular orbits and energy conversion
efficiency of accretion disks around such black holes and compare the results
with the standard general relativistic Schwarzschild solution. We find that the
accretion disks around scalarized black holes are hotter and more luminous than
in general relativity.
