Exploring CP Violation with B_d -> D K_s Decays

TL;DR

This paper investigates CP violation in B_d decays to D and K_s, proposing methods to extract unitarity triangle angles using time-dependent decay rates, with a focus on theoretically clean measurements free of penguin contributions.

Contribution

It introduces a novel approach to measure CP violation parameters in B_d decays via time-dependent rates involving D meson states, avoiding penguin diagram complications.

Findings

Methods to extract $eta$ and $eta+ heta$ angles from decay rates.

Identification of decay channels free from penguin contributions.

Potential for precise CP violation measurements in B_d 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 $B_d(t) -> {\bar D}^{**0} K_s$ and $B_d(t) -> D^{**0} K_s$, where the $D^{**0}$ decays to $D^{(*)+}\pi^-$. 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.