A method of measuring cos(2beta) using a time-dependent dalitz plot analysis of B0 - > DCPpi+pi

We present a feasibility study of a previously outlined method for measuring both the sine and the cosine of twice the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle angle beta using a time-dependent Dalitz plot analysis of B0 - > Dpi+pi- decays, where the neutral D meson is reconstructed in decays to CP eigenstates. We show that this method can be used at the B factories to make a measurement of cos(2beta) that is competitive with, or more precise than, other techniques using different quark-level transitions, while sin(2beta) can be measured to a better precision than any existing measurement using transitions. Furthermore, this technique has great potential to be employed at LHCb.