Dependence of the 1S0 superfluid pairing gap on nuclear interactions

Nucleon-nucleon (NN) interactions are well constrained for relative momenta k 2 fm−1 by existing scattering data [1]. The model dependences for larger momenta can be seen, for instance, in the P2 superfluid pairing gaps for Fermi momenta kF > 2 fm−1 [2]. In Ref. [3], we study in detail the dependence of the S0 superfluid gap on nuclear interactions at the BCS level, and on the resolution scale. For the RG evolution to low-momentum interactions Vlow k, we define a reduced interaction v(k, k′) through V (k, k′) = f(k′) v(k′, k) f(k), where f(k) denotes a sharp or smooth regulator with variable cutoff Λ. Starting from an NN interaction with large cutoff v(k, k′) = VNN(k, k′), we use the RG equation [4] dv(k′, k) dΛ = 1