Nuclear many-body effects on particle emission following muon capture on Si-28 and Ca-40

Background: Muon captures on nuclei have provided us with plenty of knowledge of nuclear properties. Recently, this reaction attracts attention in electronics, because charged particle emissions following muon capture on silicon become to trigger non-negligible soft errors in memory devices. Purpose: To date, there is no theoretical framework based on the nuclear structure that describes a muon capture reaction followed by particle emissions comprehensively. The purpose of this work is to develop a new method that considers the nuclear many-body correlation for the accurate understanding of the soft errors in memory devices. Method: We combined the second Tamm-Dancoff approximation that is used to estimate muon capture rates with the two-component exciton model, the model describing particle emission from the pre-equilibrium state. For particle evaporation from the compound state, the Hauser-Feshbach statistical models were applied. We chose 28Si and 40Ca to check the performance of the framework. Result: We paid attention to the muon capture rates, the particle emission spectra, and the multiplicities that have a close interrelation with each other. We found that the nuclear many-body correlations including two-particle two-hole excitations is a key to explaining them simultaneously. Conclusion: The present study showed that the combination of the microscopic approach of muon capture and the two-component exciton model of particle emission is an effective tool to describe particle emission following the muon captures, giving the nuclear structure information additionally. For a finer understanding of particle emission following muon capture and a validation of the present framework, further experimental studies on particle emission spectra are highly expected.