Previously, the near-threshold $\mathit{pp}\to \mathit{pp}{\pi }^0$ reaction was studied with the use of transition operators derived from chiral perturbation theory (χPT) and the nuclear wave functions generated by high-precision phenomenological potentials. A conceptual problem in that approach was that the transition amplitude receives contributions from very high momentum components (above the cutoff scale of χPT) in the nuclear wave functions. In the present work, we avoid this problem by replacing the “bare” phenomenological potentials with $V_{\mathrm{low}\text{−}k}$, which is an effective potential derived from a bare potential by integrating out momentum components higher than a specified cutoff scale. The use of $V_{\mathrm{low}\text{−}k}$ is found to give an enhancement of the $\mathit{pp}\to \mathit{pp}{\pi }^0$ cross sections over the values obtained with bare potentials. Although this enhancement brings the calculated cross sections closer to the experimental values, the incident-energy dependence of the cross section is not well reproduced, a problem that seems to indicate the necessity of including higher chiral order terms than considered in the present work.

• Received 18 October 2005

DOI:https://doi.org/10.1103/PhysRevC.73.025202