  A momentum-dependent formulation based on a stationary spin-0 and isospin-1
dibaryon field is proposed to improve convergence of chiral effective field
theory in the $\cs{1}{0}$ channel of $NN$ scattering. Although the
two-parameter leading-order interaction appears to be unnatural, it
nevertheless has the necessary features of an effective field theory. A rapid
order-by-order convergence is found in $\cs{1}{0}$. As an application beyond
the two-body level, the triton binding energy is studied and compared to
standard chiral effective field theory with partly perturbative pions. The
consistency of the chiral Lagrangian for the new formulation is examined by
working out the pionic radiative corrections, and consequences of nontrivial
chiral-connection terms are discussed.
