Tagging of B-d(0)-(B)over-bar(d)(0) using B**(+/-)-> B-d(0(*))pi(+/-) decay with the CMS experiment

A new tagging method to measure the angle beta in the unitarity triangle by the decay B-d(0) --> J/psi K-S(0) has been studied. The nature of the b-qu ark is known by the charge of the emitted pion in the B**(+/-) decay: B**(/-) --> B-d(0)((B) over bar (0)(d))(pi)(+/-). The, study, in this article p resents a accurate description of the CMS (Compact Muon Solenoid) detector performance, it also takes into account pile-up effect at low luminosity. T he expected precision of the CMS detector measurement for angle beta with t his method has been evaluated to be delta (sin 2 beta) = 0.022. (C) 2001 Pu blished by Elsevier Science B.V.