New approach to determine proton-nucleus interactions from experimental bremsstrahlung data

Abstract

A new approach is presented to determine the proton-nucleus interactions from the analysis of the accompanying photon bremsstrahlung. We study the scattering of p + 208 Pb at the proton incident energies of 140 and 145 MeV, and the scattering of p + 12 C, p + 58 Ni, p + 107 Ag and p + 197 Au at the proton incident energy of 190 MeV. The model determines contributions of the coherent emission (formed by an interaction between the scattering proton and nucleus as a whole without the internal many-nucleon structure), incoherent emission (formed by interactions between the scattering proton and nucleus with the internal many-nucleon structure), and transition between them in dependence on the photon energy. The radius-parameter of the proton-nucleus potential for these reactions is extracted from the experimental bremsstrahlung data analysis. We explain the hump-shaped plateau in the intermediate-and high-energy regions of the spectra by the essential presence of the incoherent emission, while at low energies the coherent emission predominates which produces the logarithmic shape spectrum. We provide our predictions (in absolute scale) for the angular distribution of the bremsstrahlung photons in order to test our model, results and analysis in further experiments.

Nucleon microscopy in proton-nucleus scattering via analysis of bremsstrahlung emission

“…It was shown in Ref. [29], that incoherent emission in experimental bremsstrahlung data [30] for scattering p + 208 Pb at 145 MeV of the proton beam energy is not small at low energies (at 20-120 MeV of photons emitted, see Fig. 5 for details in that paper).…”

“…However, we did not take into account anomalous magnetic momenta of nucleons in our model, calculations and analysis of bremsstrahlung experimental information. As anomalous magnetic moment for neutron is essentially different from its Dirac magnetic moment, one can suppose that after inclusion of anomalous momenta to the model changes of results [29] can be not small (for example, this can give essentially different estimation of role of incoherent emission on background of the full bremsstrahlung spectrum). So, inclusion of internal structure of nucleons to the bremsstrahlung model for nuclear reactions for energies from low to high is motivated task.…”

“…We construct a new bremsstrahlung model for proton nucleus scattering, where we include internal structure of the scattered proton. As starting basis for such developments, we use our previous formalism [28,29] applied for proton nucleus scattering. We use the first approximation of generalisation of Dirac equation to describe system of nucleons with interacting potential.…”

“…As we found, this is many-nucleon generalisation of Pauli equation with interacting potential investigated in Refs. [28,29,[31][32][33]. This way allows us to construct formalism with some connection with many-nucleon bremsstrahlung developments of other researchers [34][35][36][37][38][39][40][41][42][43][44][45][46] (here, evolution of nucleons is investigated as many body problem of quantum mechanics that allows to save quantum properties maximally completely).…”

Migdal effect and photon bremsstrahlung in effective field theories of dark matter direct detection and coherent elastic neutrino-nucleus scattering

“…This implies that the EFT nucleon operators in the amplitude must be summed over the nucleons in the target nuclei. For the bremsstrahlung process, incoherence caused by internucleon effects are neglected since it only makes a meaningful contribution at photon energies [43,44] higher than those of interest here.…”