Towards degeneracy problem breaking by large scale structures methods

An arguable aspect of the modified gravity theories is that many of them present the so-called degeneracy problem. For instance, the cosmological evolution, gravitational collapse and the main features of standard black-hole configurations, can be mimicked by many of those theories. In this communication we revise briefly the appropriate observable quantities to be measured in order to discard alternative theories to LCDM, such as the observed growth of scalar perturbations with Sloan data and the CMB tensor perturbations evolution.