1999/07/19 by S. Scherer, Scherer, S.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th) #hep-ex #hep-ph #nucl-th
paper · pdf · doi:10.48550/arxiv.hep-ph/9907416
11 pages, Latex2e, 5 postscript figures, uses ws-p8-50x6-00.cls, invited talk at the 2nd International Conference on Perspectives in Hadronic Physics, 10 - 14 May 1999, Trieste, Italy
arxiv created 1999/07/19 · arxiv updated 2009/11/30
We discuss the virtual Compton scattering amplitude γ^∗+π→ γ+π which enters the reaction π-+e-→π-+e-+γ. The low-energy scattering amplitude is divided into a model-independent part, involving only the electromagnetic form factor, and a residual part which contains structure information related specifically to (virtual) Compton scattering. In the limit of vanishing final-photon energy, the residual amplitude can be expressed in terms of three generalized dipole polarizabilities which are functions of the squared virtual-photon four-momentum. We study the VCS amplitude in the framework of chiral perturbation theory at \cal O(p4). At the one-loop level the generalized dipole polarizabilities are degenerate αL(q2)=αT(q2)=-β(q2).