Model independent sum rules for B -> pi K decays

We provide a set of sum rules relating CP-averaged branching ratios and CP- asymmetries of the B --> piK modes. They prove to be useful as a mechanism to 'test' experimental data given our expectations of the size of isospin b reaking. A set of observables emerges providing a simpler interpretation of data in terms of isospin breaking. Moreover, the derivation is done in a c ompletely model independent way, i.e., they can accommodate also New Physic s contributions. (C) 2001 Elsevier Science B.V. All rights reserved.