Spin polarization observables of the deuteron photodisintegration at low energies in pionless effective field theory

Spin polarization observables of the deuteron photodisintegration at low energies are studied in a pionless effective field theory up to next-to-next-to-leading order (NNLO). The total and differential cross sections, induced neutron polarization $P_{y}$, and tensor analyzing powers $T_{20}$ and $T_{22}$ of the process are calculated at photon energies from the breakup threshold to 20~MeV. We find that the NNLO corrections in the cross sections and $P_{y}$ converge well whereas they turn out to be important contributions in $T_{20}$ and $T_{22}$. We discuss the discrepancy between theory and experiment in $P_{y}$ still persisting as well as an implication of our result to the first measurement of $T_{20}$ at low energies in the HIGS facility.