How to employ $bar{B}^0_d to J/psi(pieta,bar{K}K)$ decays to extract information on $pieta$ scattering

We demonstrate that dispersion theory allows one to deduce crucial information on $pieta$ scattering from the final-state interactions of the light mesons visible in the spectral distributions of the decays $bar{B}^0_d to J/psi(pi^0eta,K^+K^-,K^0bar{K}^0)$. Thus high-quality measurements of these differential observables are highly desired. The corresponding rates are predicted to be of the same order of magnitude as those for $bar{B}^0_d to J/psipi^+pi^-$ measured recently at LHCb, letting the corresponding measurement appear feasible.