Chiral potentials, perturbation theory, and the 1S0 channel of NN scattering

Understand

We use nucleon-nucleon phase shifts obtained from experimental data, together with the chiral expansion for the long-distance part of the NN interaction, to obtain information about the short-distance piece of the NN potential that is at work in the 1S0 channel.

• We find that if the scale R that defines the separation between &#34;long-&#34; and &#34;short-&#34; distance is chosen to be \lsim 1.8 fm then the energy dependence produced by short-distance dynamics is well approximated by a two-term polynomial for Tlab < 200 MeV.
• We also find that a quantitative description of NN dynamics is possible, at least in this channel, if one treats the long-distance parts of the chiral NN potential in perturbation theory.
• However, in order to achieve this we have to choose a separation scale R that is larger than 1.0 fm.