A method of measuring cos(2β) using a time-dependent dalitz plot analysis ofB⁰→DCPπ⁺π⁻

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 β using a time-dependent Dalitz plot analysis of B 0 → D π + π − 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(2β) that is competitive with, or more precise than, other techniques using different quark-level transitions, while sin(2β) can be measured to a better precision than any existing measurement using transitions. Furthermore, this technique has great potential to be employed at LHCb.