2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41090In this talk we show that, unlike other pure $b\to d$ penguin processes, the decay $\bs(t)\toϕ\ks$ is dominated by a single amplitude, that of the internal $t$-quark. Thus, the indirect CP asymmetry in this decay probes $\sin 2β$. This cancellation holds for most part of the parameter space and error on $\sin 2β$ is less than 10%. By measuring the direct CP asymmetry, one can get a better idea of the probable error on $\sin 2β$.6 pages, Latex, Talk presented at MRST 2001High Energy Physics - Phenomenologytext