  We analyze the competition between strong correlations and dissipation in
quantum impurity systems from the Kondo regime to the valence fluctuation
regime by developing a slave-boson theory for a non-Hermitian Anderson impurity
model with one-body loss. Notably, in the non-Hermitian Kondo regime, strong
correlations qualitatively change the nature of dissipation through
renormalization effects, where the effective one-body loss is suppressed and
emergent many-body dissipation characterized by the complex-valued
hybridization is generated. We unveil the mechanism of a dissipative quantum
phase transition of the Kondo state on the basis of this renormalization
effect, which counterintuitively enhances the lifetime of the impurity against
loss. We also find a crossover from the non-Hermitian Kondo regime to the
valence fluctuation regime dominated by one-body dissipation. Our results can
be tested in a wide variety of setups such as quantum dots coupled to
electronic leads and quantum point contacts in ultracold Fermi gases.
