  We report in this paper a study in terms of the nuclear shell model about the
location of the calcium isotopes drip line. The starting point is considering
the realistic two-body potential derived by Entem and Machleidt within chiral
perturbation theory at next-to-next-to-next-to-leading order (N3LO), as well as
a chiral three-body force at next-to-next-to-leading order (N2LO) whose
structure and low-energy constants are consistent with the two-body potential.
Then we construct the effective single-particle energies and residual
interaction needed to diagonalize the shell-model Hamiltonian. The calculated
two-neutron separation energies agree nicely with experiment until 56Ca, which
is the heaviest isotope whose mass has been measured, and do not show any sign
of two-neutron emission until 70Ca. We discuss the role of the choice of the
model space in determining the neutron drip line, and also the dependence of
the results on the parameters of the shell-model Hamiltonian.
