Deuteron Compton scattering in effective field theory and spin-independent nucleon polarizabilities

Deuteron Compton scattering is calculated to O(Q2) in pionless effective field theory using a dibaryon approach. The vector amplitude, which was not included in the previous pionless calculations, contributes to the cross section at O(Q2) and influences significantly the extracted values of nucleon electric polarizability at incident photon energy 49 MeV. We recommend future high precision deuteron Compton scattering experiments being performed at 25-35 MeV photon energy where the nucleon polarizability effects are appreciable and the pionless effective field theory is most reliable. For example, a measurement at 30 MeV with a 3% error will constrain the isoscalar nucleon electric polarizability α0 with a ∼30% error.