Radiative corrections to low-energy ππ scattering

Radiative corrections to low-energy ππ scattering are calculated. A chiral SU(2) × SU(2) Lagrangian is used to describe low-energy scattering. This strong interaction Lagrangian is modified in the presence of the electromagnetic field in a gauge invariant way. It is found that photons do not probe the strong vertex. Corrections to the cross sections are calculated to O(α). All the ultra-violet divergences cancel, and the results are independent of cut-off parameters. Corrections to the Weinberg scattering lengths of the order of 1% are defined by removal of the Coulomb pole terms. The field theoretic calculation is compared with a potential theory approach. It is argued that the potential theory calculation of radiative corrections is more reliable.     

Polymer bound pyrrole compounds. Reversible anchoring of bilirubin and biliverdin to a polystyrene matrix

Both bilirubin and biliverdin, $\text{via}$ their cesium salts, have been covalently attached to an insoluble polystyrene matrix (the so-called Nbb-resin), some chemical transformations have been carried out upon the supported pigments, and the resulting products have been detached by alkaline methanol.