Electromagnetic Polarizabilities: Lattice QCD in Background Fields

Understand

Chiral perturbation theory makes definitive predictions for the extrinsic behavior of hadrons in external electric and magnetic fields.

• Near the chiral limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons are determined in terms of a few well-known parameters.
• In this limit, hadrons become quantum mechanically diffuse as polarizabilities scale with the inverse square-root of the quark mass.
• In some cases, however, such predictions from chiral perturbation theory have not compared well with experimental data.