Neutral pion photoproduction off 3H and 3He in chiral perturbation theory

Neutral pion photoproduction on nuclei in baryon chiral perturbation theory.

Pion–Pion and Pion–Nucleon Interactions in Chiral Perturbation Theory*

Elastic pion–pion and pion–nucleon scattering are reviewed in the context of chiral perturbation theory. Theoretical results from systematic low–energy expansions to O(p) for ππ and to O(p) for πN are compared with experimental data. Possible future developments are outlined. Talk given at the Workshop on Chiral Dynamics 1997 Mainz, Germany, Sept. 1 5, 1997 To appear in the Proceedings * Work s...

Pion Scattering in Wilson Chiral Perturbation Theory

We compute the scattering amplitude in Wilson Chiral Perturbation Theory for two flavors. The lattice spacing effects due to the explicit chiral symmetry breaking are kept through O(a2), and we consider the regime where the quark mass m is of order aΛQCD. Analytic expressions for the scattering lengths in different isospin channels are given. As a result of the O(a2) terms the scattering length...

Aspects of near threshold neutral pion photoproduction off protons

We investigate near threshold neutral pion photoproduction off protons to fourth order in heavy baryon chiral perturbation theory in the light of the new data from MAMI. We show that the unitarity cusp at the secondary πn threshold is in agreement with expectations from the final state theorem. We also analyze the fourth order corrections to the P–wave low–energy theorems and show that potentia...

Unitarity constraint for threshold coherent pion photoproduction on the deuteron and chiral perturbation theory

The contribution of the two-step process γd → pn → π0d to the imaginary part of the amplitude for coherent pion production on the deuteron is calculated exploiting unitarity constraints. The result shows that this absorptive process is not negligible and has to be considered in an extraction of the elementary neutron production amplitude from the γd → π0d cross section at threshold. In addition...