  In this work, we investigate the quasinormal modes for a massive scalar field
with a nonminimal coupling with gravity in the spacetime of a loop quantum
black hole, known as the Self-Dual Black Hole. In this way, we have calculated
the characteristic frequencies using the 3rd order WKB approach, where we can
verify a strong dependence with the mass of scalar field, the parameter of
nonminimal coupling with gravity, and parameters of the Loop Quantum Gravity.
From our results, we can check that the Self-Dual Black Hole is stable under
the scalar perturbations when assuming small values for the parameters. Also,
such results tell us that the quasinormal modes assume different values for the
cases where the mass of field is null and the nonminimal coupling assumes
$\xi=0$ and $\xi=1/6$, i.e., a possible breaking of the conformal invariance
can be seen in the context of loop quantum black holes.
