Search for the W-exchange decays B0 --> Ds(*)- Ds(*)+

TL;DR

This study searches for specific W-exchange decay modes of B0 mesons into Ds(*)- Ds(*)+ pairs using a large data sample, but finds no significant signals and sets upper limits on their branching fractions.

Contribution

First search for these W-exchange B0 decay modes, providing upper bounds on their branching fractions with a large data sample from BaBar.

Findings

No significant signals detected.

Set upper bounds on branching fractions.

Improved constraints on rare B0 decay modes.

Abstract

We report a search for the decays $B^{0} \to D_{s}^{-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{*+}$ in a sample of 232 million $\Upsilon(4S)$ decays to \BBb ~pairs collected with the \babar detector at the PEP-II asymmetric-energy $e^+ e^-$ storage ring. We find no significant signal and set upper bounds for the branching fractions: ${\cal B}(B^{0} \to D_{s}^{-} D_{s}^{+}) < 1.0 \times 10^{-4}, {\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{+}) < 1.3 \times 10^{-4}$ and ${\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{*+}) < 2.4 \times 10^{-4}$ at 90% confidence level.