Dependence of the 1S0 superfluid pairing gap on nuclear interactions

We study in detail the dependence of the 1S0 superfluid pairing gap on nuclear interactions and on charge-independence breaking at the BCS level. Starting from chiral effective-field theory and conventional nucleon-nucleon interactions, we use the renormalization group to generate low-momentum interactions Vlowk with the sharp and smooth regulators. The resulting BCS gaps are well constrained by the nucleon-nucleon scattering phase shifts, and the cutoff dependence is very weak for sharp or sufficiently narrow smooth regulators with the cutoffs A > 1.6 fm-1. It is therefore likely that the effect of three-nucleon interactions on 1S0 superfluidity is small at the BCS level. The charge dependence of nuclear interactions has a 10% effect on the pairing gap. (orig.)