New Photodisintegration Model of GEANT4 for the $d\gamma \to np$ Reaction with a Dibaryon Effective Field Theory

Abstract

We develop a new hadronic model for GEANT4 that is specialized for the disintegration of the deuteron by photons, $d\gamma \to n p$. For the description of two-nucleon interactions, we employ a pionless effective field theory with dibaryon fields (dEFT). We apply the new model of GEANT4 (G4dEFT) to the calculations of the total and the differential cross sections in $d\gamma \to n p$ and compare the results with empirical data. As an application of the new model, we calculate the neutron yield from the $\gamma + {\rm CD}_2$ process. G4dEFT predicts peaks for the neutron yield, but the existing model of GEANT4 does not show such behavior.