Photodisintegration of ultra-high-energy cosmic rays revisited

Abstract

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 10 20−21 eV. At energies around 10 20 eV, the new cross sections are found to modify the UHECR photodisintegration rates. At energies around 10 21 eV, it is recommended to solve a full reaction network to estimate the photodisintegration rate of the UHECR.

Extragalactic propagation of ultrahigh energy cosmic-rays

“…The possibility of the presence of nuclei heavier than iron was furthermore studied by Anchordoqui et al [36] while Bertone et al [37] considered the effect of magnetic fields on the propagation of heavy nuclei and tested some astrophysical models for the origin of UHECRs. More recently, Khan et al [38], proposed new estimates of the GDR cross section, based on theoretical calculation using the TALYS nuclear reaction code [39,40], showing a better agreement with the available data than previous parametrizations from [32]. In recent years the interest in the propagation of UHECR nuclei has significantly grown [41,42,43,44,45,46,47,48,49].…”

“…the different channels can highly vary from one nucleus to another, some nuclei, for instance, being more likely to emit a proton or sometimes an α particle depending on the detail of its nuclear structure [38].…”

Constraints on the origin of ultra-high-energy cosmic rays from cosmogenic neutrinos and photons

“…The nucleon pion production, which leads to the production of photons, neutrinos and electrons or positrons, was simulated using the SOPHIA event generator (Mucke et al 2001). In the case of nuclei, the different channels of the giant dipole resonance (GDR) were modeled using the theoretical calculations from Khan et al (2005) and parametrizations from Rachen (1996) for nuclei with mass A ≤ 9. Cross sections and nucleon yield for the quasi-deuteron and pion production (baryonic resonances) were also treated using Rachen (1996).…”

Interactions of UHE cosmic ray nuclei with radiation during acceleration: consequences for the spectrum and composition

“…The GDR process is the most relevant as it has the highest cross section and the lowest thresholds, between 10 and 20 MeV, for all nuclei. For nuclei with mass A ≥ 9, we use the theoretical GDR cross sections presented by Khan et al (2005), which take into account all the individual reaction channels (n, p, 2n, 2p, np, α, . .…”