Decay of a Quasiparticle in a Quantum Dot: The Role of Energy Resolution

The disintegration of a quasiparticle in a quantum dot due to electron interaction is considered. It was predicted recently that above the energy ${\varepsilon }^{*}=\Delta (g/\ln g{)}^{1/2}$ each one particle peak in the spectrum is split into many components. We show that the observed value of ${\varepsilon }^{*}$ should depend on the experimental resolution $\delta \varepsilon$. In the broad region of variation of $\delta \varepsilon$ the $\ln g$ term should be replaced by $\ln \left(\Delta /g\delta \varepsilon \right)$. We also argue against delocalization transition in the Fock space. Most likely the number of satellite peaks grows continuously with energy. The predicted logarithmic distribution of interpeak spacings may be used for experimental confirmation of the below-golden-rule decay.