Description
In this contribution to the call for input for the NuPECC Long Range Plan 2024, we describe the PANDORA project, which aims to systematically measure the photonuclear response of nuclei with mass lighter than iron. There is strong need of good quality photo-nuclear reaction data for most of the light nuclei of astrophysical interest below iron. The situation is further crippled by the non-availability of reliable theoretical means for required photo-nuclear cross sections since the prediction of mean field theories and statistical models, well suited for heavy nuclei, does not agree well with measured values in this region. The ab-initio calculations have been used only for few of the lightest isotopes beyond which it becomes cumbersome to accommodate the large model space. These measurements would lead to new insights for the effect of clustering, shell structure, and NN correlations on the photo-nuclear response of these nuclei.
A particular interest regarding the applications for this project is the effect of photodisintegration calculations on the propagation of ultra-high energy cosmic rays (UHECR). The primary disintegration of the UHECRs in extra-galactic space is through the interaction of the particle species with the strongly Doppler-shifted cosmic microwave background leading to photo-nuclear reactions mainly in the GDR region. Working in synergy with the UHECR theory groups, the PANDORA project is intending to provide reliable photo-nuclear cross section inputs for a large set of nuclei. This would significantly improve our understanding in the UHECR propagation and generation model.