3 research outputs found
Deconstructing 1S0 nucleon-nucleon scattering
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. This may
signal the need to include the Delta resonance as an explicit degree of freedom
in order to describe scattering at these energies. An alternative strategy of
keeping the cutoff finite to reduce large, but finite, contributions from the
long-range forces is also discussed.Comment: 10 pages, 2 figures (introduction revised, references added; version
to appear in EPJA
Nucleon-Nucleon Interaction and Isospin Violation
The application of the chiral effective theory to processes with two or more
nucleons is discussed. We gain a qualitative understanding of the gross
features of nuclear physics and quantitative, testable postdictions and
predictions involving photons and pions.Comment: 17 pages, 2 ps figures, uses lamuphys.sty and epsfig.sty; invited
plenary talk at the Chiral Dynamics Workshop, Mainz, Sept 1-5 199