The Hidden Variables: Harnessing Half-Shell Potentials for Enhanced Precision in Nuclear Reaction Calculations

We explore the impact of half-shell components on nuclear reaction calculations, focusing on nonelastic breakup cross sections within the Ichimura-Austern-Vincent (IAV) model. By advocating for the use of a consistent Single Folding Model (SFM) for all optical potentials in IAV calculations, we aim to reduce the uncertainties associated with half-shell components and enhance agreement with experimental data. We present results from deuteron-induced reactions on $^{60}$Ni and $^{208}$Pb, which serve as surrogate targets for neutron-induced reactions on short-lived nuclei. The application of consistent optical potentials derived from the SFM shows improved alignment with experimental data compared to traditional global phenomenological potentials. Furthermore, we investigate the $^{59}$Co($^6$Li,$\alpha X$) reaction, which reveals that the half-shell $T$-matrix plays a pivotal role in accurately modeling nuclear reactions. Our findings suggest that a unified approach to optical potentials, accounting for half-shell effects, is critical for a precise understanding of complex nuclear reactions. This work highlights the significance of the internal dynamics of the wave function, particularly in lighter targets, and underscores the importance of the half-shell $T$-matrix as a previously underappreciated variable in reaction calculations.