Chiral Perturbation Theory Calculations For S-wave ${\pi }^0$ production In pp Collision

Abstract

The total cross section for the pp --> pp ${\pi }^0$ reaction at energies close to threshold is calculated within the frame of a chiral perturbation theory. The tree and one loop diagrams up to chiral order D=2 contributions are taken into account. The $L^{(0)}$ isoscalar-scalar part of t-channel two-pion exchange loop diagrams enhances the production amplitude strongly. The calculated cross section scale and energy dependence are very close to data.

REVTeX, 15 pages including figures, 4 postscript figures