Exploring CP Violation with B_d -> D K_s Decays

Abstract

We (re)examine CP violation in the decays B_d -> D K_s, where D represents D^0, D(bar), or one of their excited states. The quantity ${\sin }^2(2\beta +\gamma )$ can be extracted from the time-dependent rates for $B_d(t)->{\bar{D}}^{\ast \ast 0}{K}_s$ and $B_d(t)->D^{\ast \ast 0}{K}_s$, where the $D^{\ast \ast 0}$ decays to $D^{(\ast )+}{\pi }^{-}$. If one considers a non-CP-eigenstate hadronic final state to which both D(bar) and D^0 can decay (e.g. $K^{+}{\pi }^{-}$), then one can obtain two of the angles of the unitarity triangle from measurements of the time-dependent rates for $B_d(t)->(K^{+}{\pi }^{-}{)}_{D{K}_s}$ and $B_d(t)->(K^{-}{\pi }^{+}{)}_{D{K}_s}$. There are no penguin contributions to these decays, so all measurements are theoretically clean.

Comments: 15 pages, LaTeX, no figures