Deconstructing 1S0 nucleon-nucleon scattering

Understand

A distorted-wave method is used to analyse nucleon-nucleon scattering in the 1S0 channel.

• Effects of one-pion exchange are removed from the empirical phase shift to all orders by using a modified effective-range expansion.
• Two-pion exchange is then subtracted in the distorted-wave Born approximation, with matrix elements taken between scattering waves for the one-pion exchange potential.
• The residual short-range interaction shows a very rapid energy dependence for kinetic energies above about 100 MeV, suggesting that the breakdown scale of the corresponding effective theory is only 270MeV.