Low-momentum nucleon-nucleon potential and its separability

Using the Okubo effective theory a realistic nucleon-nucleon potential is transformed into low-momentum effective one (LMNN). The feature of the LMNN potential is examined by calculating the triton binding energy, in order to see the dependence of the cutoff parameter Λ. Furthermore, the LMNN is expanded in a separable form. We compare the universal separable expansion method with a simple Legendre expansion. Through the calculation of the triton binding energies, the separability for the convergence of these ranks is evaluated. It is found that there is a tendency for the lower Λ of LMNN to gain better separability.