Consistent optical potential for incident and emitted low-energy ? particles. III. Nonstatistical processes induced by neutrons on Zr, Nb, and Mo nuclei

Background: The reliability of a previous alpha-particle optical-model potential (OMP) on nuclei with mass number 45 A 209 was proved for emitted alpha particles as well, for proton-induced reactions on Zn isotopes [Phys. Rev. C 91, 064611 (2015), Paper I]. However, the same was not the case of neutrons on Zr stable isotopes [Phys. Rev. C 96, 044610 (2017), Paper II].Purpose: A recent assessment of this potential also for nucleon-induced alpha emission on A approximate to 60 nuclei, including pickup direct reaction and eventual giant quadrupole resonance (GQR) alpha emission, was completed for neutrons incident on Zr, Nb, and Mo stable isotopes.Methods: Consistent sets of input parameters, determined through analysis of independent data, are involved while no further empirical rescaling factors of the gamma and nucleon widths have been involved.Results: A suitable account of all competitive reaction channels is confirmed by careful uncertainty analysis, to avoid parameter ambiguities and/or error compensation. Additional validation of this potential is also supported by recently measured (alpha, gamma) and (alpha, n) cross sections of Zr and Mo nuclei.Conclusions: An increase of the alpha emission beyond the statistical predictions, through consideration of additional reaction channels of the pickup direct interaction and GQR-like decay, makes possible the description of both absorption and emission of alpha particles by the same optical potential.

Automated summary

The reliability of a previous alpha-particle optical-model potential (OMP) has been confirmed for proton-induced reactions on Zn isotopes and neutrons on Zr stable isotopes. A recent assessment of this potential for nucleon-induced alpha emission on A approximately 60 nuclei, including pickup direct reaction and eventual giant quadrupole resonance (GQR) alpha emission, was completed. Consistent sets of input parameters were determined through analysis of independent data to avoid parameter ambiguities and/or error compensation.