Pion polarisabilities and bremsstrahlung

A model for high-energy, small-angle pion-nucleus bremsstrahlung, $\pi^- +A\to\pi^- +\gamma +A$,is developed within the Glauber diffraction theory. Special attention is focussed on the possibility of measuring the pion polarisability in such reactions. That is the case under the Coulomb peak provided the bremsstrahlung photon carries practically all the energy of the incident pion. Only radiation from external legs is considered.