Measuring $\beta$ in $B \to D^{*+}D^{*-}K_s$ Decays

TL;DR

This paper proposes using the decay $B^0 o D^{*+}D^{*-}K_s$ to measure both $ an(2eta)$ and $ an(2eta)$, offering a higher branching fraction and potential insights into the $D_s$ meson spectrum.

Contribution

It introduces a method to measure both $ an(2eta)$ and $ an(2eta)$ using a specific decay mode with higher branching fraction, and explores the spectrum for new meson states.

Findings

Estimated branching fraction and polarization using theoretical models.

Potential to measure $ an(2eta)$ and $ an(2eta)$ from time-dependent decay rates.

Identification of a promising spectrum region for discovering broad $1^+$ $D_s$ mesons.

Abstract

We consider the possibility of measuring both $\sin (2 \beta)$ and $\cos (2 \beta)$ in the KM unitarity triangle using the process $B^0 \to D^{*+}D^{*-}K_s$. This decay mode has a higher branching fraction (O(1%)) than the mode $B^0 \to D^{*+}D^{*-}$. We use the factorization assumption and heavy hadron chiral perturbation theory to estimate the branching fraction and polarization. The time dependent rate for $B^0(t) \to D^{*+} D^{*-} K_s$ can be used to measure $\sin (2 \beta)$ and $\cos(2 \beta)$ . Furthermore, examination of the $D^{*+} K_s$ mass spectrum may be the best way to experimentally find the broad $1^+$ p-wave $D_s$ meson.