Measurement of Sin(2beta) in Tree Dominated B0 Decays And Ambiguity Removal

The most recent results from the B-factories on the time-dependent CP asymmetries measured in B⁰-decays mediated by b → c(bar c)s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin 2β leads to a four-fold ambiguity on the unitarity triangle β which can be reduced to a two-fold ambiguity by measuring the sign of the parameter cos 2β. The results on cos2β obtained so far are reviewed