Effective field theory of the deuteron with dibaryon fields

Pionless effective field theory with dibaryon fields is reexamined for observables involving the deuteron. The electromagnetic form factors of the deuteron and the total cross section of radiative neutron capture on the proton, np -> d gamma, are calculated. The low-energy constants of vector-(photon-)dibaryon-dibaryon vertices in the effective Lagrangian are fixed primarily by the one-body vector-(photon-)nucleon-nucleon interactions. This scheme for fixing the values of the low-energy constants satisfactorily reproduces the results of the effective range theory. We also show that, by including higher-order corrections, we can obtain results that are close to those of the Argonne v18 potential model.