Measurement of BR(B0 -> Ds*+D*-) and Determination of the Ds+ -> phi pi+ Branching Fraction with a Partial-Reconstruction Method

TL;DR

This paper reports model-independent measurements of specific B and D_s+ meson decay branching fractions using partial reconstruction techniques on data from the BABAR detector, providing precise results for these decay modes.

Contribution

The study introduces a partial-reconstruction method for measuring B and D_s+ decay branching fractions, reducing model dependence and improving measurement accuracy.

Findings

Measured ${ m BR}(B^0 o D_s^{*+} D^{*-}) = (1.50 \u00b1 0.16 \u00b1 0.12) ext{%}$

Determined ${ m BR}(D_s^+ o \u03a6 \u03c6^+) = (4.7 \u00b1 0.6 \u00b1 0.8) ext{%}$

Used 19.3 fb^{-1} data from BABAR with partial reconstruction techniques.

Abstract

We present model-independent measurements of the branching fractions ${\cal B}(B^0\to D_s^{*+} D^{*-})$ and ${\cal B}(D_s^+ \to \phi \pi^+)$ based on 19.3 $\textup{fb}^{-1}$ of data collected by the $BABAR$ detector at the PEP-II $e^+e^-$ $B$ Factory. Neutral $B$-meson decays to the $D_s^{*+}D^{*-}$ final state are selected with a partial reconstruction of the $D_s^{*+}$; that is, only the $D^{*-}$ and the soft photon from the decay $D_s^{*+} \to \Ds \gamma$ are reconstructed. The branching fraction ${\cal B}(B^0\to D_s^{*+} D^{*-})$ is extracted from these event yields, while ${\cal B}(D_s^+ \to \phi \pi^+)$ is determined by combining this result with a previous measurement of the product ${\cal B}(B^0\to D_s^{*+} D^{*-}) \times {\cal B}(D_s^+ \to \phi \pi^+)$ with partial reconstruction of the $D^{*-}$. We obtain the following preliminary results: ${\cal B}(B^0\to D_s^{*+} D^{*-}) = (1.50 \pm 0.16 \pm 0.12)%,$ ${\cal B}(D_s^+ \to \phi \pi^+) = (4.7 \pm 0.6 \pm 0.8)%$ where the first error is statistical, and the second systematic.