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Neutrino-induced neutron spallation and supernova r-process nucleosynthesis

Y. -Z. Qian·W. C. Haxton·K. Langanke·P. Vogel
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Abstract

In order to explore the consequences of the neutrino irradiation for the supernova r-process nucleosynthesis, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich heavy nuclei, and estimate the average number of neutrons emitted in the resulting spallation. Our results suggest that charged-current $ν_e$ captures can be important in breaking through the waiting-point nuclei at N=50 and 82, while still allowing the formation of abundance peaks. Furthermore, after the r-process freezes out, there appear to be distinctive neutral-current and charged-current postprocessing effects. A subtraction of the neutrino postprocessing effects from the observed solar r-process abundance distribution shows that two mass regions, A=124-126 and 183-187, are inordinately sensitive to neutrino postprocessing effects. This imposes very stringent bounds on the freeze-out radii and dynamic timescales governing the r-process. Moreover, we find that the abundance patterns within these mass windows are entirely consistent with synthesis by neutrino interactions. This provides a strong argument that the r-process must occur in the intense neutrino flux provided by a core-collapse supernova.

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Y. -Z. Qian, W. C. Haxton, K. Langanke, P. Vogel. 1996-11-05. Neutrino-induced neutron spallation and supernova r-process nucleosynthesis. https://doi.org/10.1103/physrevc.55.1532

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