arXiv subjects

Hibiki Nakada

Publications and source records attributed to Hibiki Nakada.

3 recordsLinked to original sources

arXiv2025

Systematic analysis of proton- and deuteron-induced one-proton knockout reactions

The ratios of the one-proton knockout cross sections by a deuteron to those by a proton are about 1.5, indicating that using deuteron is more efficient than proton in yielding large knockout cross sections. However, this ratio differs from the intuitive expectation, and its underlying mechanism remains unclear. The purpose of this study is to clarify the mechanism behind the observed ratio by theoretically describing and analyzing the deuteron- and proton-induced one-proton knockout reactions. Proton-induced one-proton knockout reactions are described within the standard distorted-wave impulse approximation (DWIA) framework, while deuteron-induced one-proton knockout reactions are treated with a new approach, DWIA-BU, that incorporates deuteron breakup into the DWIA. The ratios calculated with the DWIA-BU reproduce the experimental data reasonably, whereas those with the DWIA significantly underestimate them. The ratio of the corresponding elementary cross sections remains about 3.5 regardless of the energy, and the difference in absorption between the deuteron and the proton influences the ratios of knockout cross sections, resulting in agreement between the calculated ratios and the experimental data. It is found that the deuteron breakup is essential to reproduce the experimental ratio. The ratios of the knockout cross sections are primarily determined by the difference in the elementary cross sections and that in the absorption between the deuteron and the proton.

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arXiv2024

Difference in peripherality of the inclusive (p, p'x) and (d, d'x) reactions and its implications for phenomenological reaction model

Previous studies have revealed the importance of introducing surface correction into a phenomenological model for inclusive (n, n'x) and (p, p'x) reactions. These findings have contributed significantly to the improvement of nuclear data evaluation. However, the necessity for the surface correction in an inclusive (d, d'x) reaction has hardly been investigated. The purpose of this study is to investigate the difference in the peripherality of the (p, p'x) and (d, d'x) reactions by a theoretical analysis using a quantum mechanical model, and to obtain a theoretical basis on the surface correction in the (d, d'x) reaction. The energy spectra and their radial distributions for the (p, p'x) and (d, d'x) reactions are calculated by the one-step semiclassical distorted wave model. The radial distribution of the energy spectra for the (d, d'x) reaction is shifted toward the outer region of the nucleus compared to the (p, p'x) reaction. Based on this finding, we consider a larger surface correction into a phenomenological model for the (d, d'x) reaction than that for the (p, p'x) reaction, and calculated values reproduce the experimental (d, d'x) spectra well. The peripherality of the (d, d'x) reaction is more prominent than that of the (p, p'x) reaction. The stronger surface correction thus should be introduced for the (d, d'x) reaction than for the (p, p'x) reaction.

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arXiv2023

Description of inclusive $(d,d^{\prime}x)$ reaction with the semiclassical distorted wave model

The description of deuteron-induced inclusive reactions has been an important subject in direct nuclear reaction studies and nuclear data science. For proton-induced inclusive processes, the semiclassical distorted wave model (SCDW) is one of the most successful models based on quantum mechanics. We improve SCDW for deuteron-induced inclusive processes and clarify the importance of the proper treatment of the kinematics of the deuteron inside a nucleus. The double differential cross section (DDX) of the inclusive deuteron-emission process $(d,d^{\prime}x)$ is described by one-step SCDW. The changes in the kinematics due to the distortion effect, the refraction effect, is taken into account by the local semiclassical approximation (LSCA). The calculated DDXs of $(d,d^{\prime}x)$ reasonably reproduce experimental data in the small energy-transfer region and at forward and middle angles with some exceptions. The angular distributions of $(d,d^{\prime}x)$ are improved by including the refraction effect. The proper treatment of the changes in the kinematics of the deuteron inside a nucleus is necessary in describing the ($d$,$d'x$) reaction. The effect of the changes on the DDX of $(d,d^{\prime}x)$ is significant compared to on the proton-induced inclusive process $(p,p^{\prime}x)$ because of the stronger distortion effect on the deuteron.

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