Photodisintegration of ultra-high-energy cosmic rays revisited

Recent microscopic and phenomenological calculations of giant dipole resonances for A ⩽ 56 nuclei are presented. The derived photodisintegration cross sections are exhaustively compared to the photonuclear data available to date. An accurate description of the data is found. Our new calculations are also compared with the previous and widely-used estimates of Puget, Stecker and Bredekamp. The present calculations also include all the possible paths down the nuclear chart. The impact on the photodisintegration of ultra-high-energy cosmic rays (UHECR) is illustrated for a Fe source with typical energies of 1020–1021 eV. At energies around 1020 eV, the new cross sections are found to modify the UHECR photodisintegration rates. At energies around 1021 eV, it is recommended to solve a full reaction network to estimate the photodisintegration rate of the UHECR.