On Partial Compositeness and the CP asymmetry in charm decays

Recently, the LHCb and CDF Collaborations reported the measure of an unexpectedly large direct CP asymmetry in D meson decays. In this paper we ask if new physics associated with Partial Compositeness could plausibly explain this result. We find that Composite Higgs models with mass scale around 10 TeV can account for it, while marginally satisfying all other flavor constraints in the quark sector. The minimal framework is however inadequate in the lepton sector due to the strong constraint from mu -> e gamma. This tension can be efficiently alleviated by realizing Partial Compositeness within Supersymmetry. The resulting models can saturate the CP asymmetry in D decays for superpartner masses close to the TeV scale and somewhat large A-terms. The supersymmetric realization of Partial Compositeness also offers a predictive and phenomenologically viable organizing principle for R-parity violation, and may result in very distinctive signatures at hadron colliders. With or without Supersymmetry, the neutron EDM is expected to be around the present experimental sensitivity. (C) 2012 Elsevier B.V. All rights reserved.