The physical and mathematical properties of the composed Reissner-Nordstr\"om-black-hole-massive-scalar-field system are studied { \it analytically} in the dimensionless large-mass $M\mu\gg1$ regime [here $\{ M,\mu\}$ are respectively the mass of the central black hole and the proper mass of the scalar field]. It is proved that, for a given value ${ \bar Q}\equiv Q/M$ of the dimensionless charge parameter of the central black hole, the system is characterized by the presence of quasi-resonances, linearized perturbation modes with arbitrarily long lifetimes. In particular, using analytical techniques, we determine the black-hole-field critical mass spectrum $\{ M\mu_{ \text{ crit}}({ \bar Q})\}$ which characterizes the long-lived resonances of the composed physical system.
Categories: gr-qc