On determining CKM angles α and β

Because the B d → J/ψK S asymmetry determines only sin 2β, a discrete ambiguity in the true value of β remains. This note reviews how the ambiguity can be removed. Extractions of the CKM angle α are discussed next. Some of the methods require very large data samples and will not be feasible in the near future. In the near future, semi-inclusive CP-violating searches could be undertaken, which are reviewed last. The primary goal of the various B-factories is to test most incisively the standard CKM (Cabibbo-Kobayashi-Maskawa) [1] description of CP violation. For that purpose, the CKM angle β extraction via the " golden " B d → J/ψK S asymmetry [2] can be contrasted to those via the B → φK S , η ′ K S , DD, D 0 CP ρ 0 , etc. asymmetries. Any significant discrepancy in the measured β values indicates physics beyond the standard model [3]. The CKM predictions can be tested more incisively by removing discrete CKM ambiguities. The CP-violating asymmetry of B d → J/ψK S allows the determination of sin 2β [2, 4]. A discrete ambiguity in determining β ∈ [0, 2π) remains. Measuring cos 2β removes the ambiguity partially and can be accomplished, either by (a) correlating B s (t) → J/ψφ with B d (t) → J/ψ(π 0 K S) K * [B d (t) → J/ψρ 0 ] decays [5]. (b) studying the decay-time (t K) of the produced neutral kaon [6, 7] in the process B d (t) → J/ψ (−)