Effective Field Theory for Low-Energy Two-Nucleon Systems

We illustrate how effective field theories work in nuclear physics by using an effective Lagrangian in which all other degrees of freedom than the nucleonic one have been integrated out to calculate the low-energy properties of two-nucleon systems, viz, the deuteron properties, the np 1S0 scattering amplitude and the M1 transition amplitude entering into the radiative np capture process. Exploiting a finite cut-off regularization procedure, we find all the two-nucleon low-energy properties to be accurately described with little cut-off dependence, in consistency with the general philosophy of effective field theories.