Pion and sigma polarizabilities and radiative transitions

Abstract

Fermilab E781 plans measurements of γ-Sigma and γ-pion interactions using a 600 GeV beam of Sigmas and pions, and a virtual photon target. Pion polarizabilities and radiative transitions will be measured in this experiment. The former can test a precise prediction of chiral symmetry; the latter for a 1 (1260) → πγ is important for understanding the polarizability. The experiment also measures polarizabilities and radiative transitions for Sigma hyperons. The polarizabilities can test predictions of baryon chiral perturbation theory. The radiative transitions to the Σ * (1385) provide a measure of the magnetic moment of the s-quark. Previous experimental and theoretical results for γπ and γΣ interactions are given. The E781 experiment is described.

Kaon polarizabilities in chiral perturbation theory

“…The experimental situation on kaon polarizabilities is very poor at the moment. One could however expect an improvement in the future either in the projected kaon factories like DAΦNE in Frascati (see [11] for a thorough review of its physics capabilities) or in the high energy beam experiments at Fermilab and CERN (see [12,13] and references therein). We will see that in particular the neutral kaon polarizabilities can offer a nice way to test hadronic models which predict related form factors in the kaon system.…”