More Benefits of Semileptonic Rare B Decays at Low Recoil: CP Violation

Understand

We present a systematic analysis of the angular distribution of Bbar -> Kbar^\ast (-> Kbar pi) l^+ l^- decays with l = e, mu in the low recoil region (i.e.

• at high dilepton invariant masses of the order of the mass of the b-quark) to account model-independently for CP violation beyond the Standard Model, working to next-to-leading order QCD.
• From the employed heavy quark effective theory framework we identify the key CP observables with reduced hadronic uncertainties.
• Since some of the CP asymmetries are CP-odd they can be measured without B-flavour tagging.