A Search for the Rare Decay B0 --> D_S+ rho-

TL;DR

This paper reports a search for the rare decay B0 --> D_S+ rho- using data from BaBar, setting upper limits on its branching fraction and related amplitude ratios due to no significant signal detection.

Contribution

It provides the first experimental upper limits on the branching fraction and amplitude ratio for the decay B0 --> D_S+ rho- based on a large data sample.

Findings

No significant excess observed above background.

Set a 90% C.L. upper limit on Br(B0 --> D_S+ rho-)< 1.9×10^{-5}.

Set a limit on the amplitude ratio r(D rho)<9.5×10^{-3}.

Abstract

We report on a search for the decay B0 --> D_S+ rho- in a sample of 90 million Y(4S) decays into B meson pairs collected between 1999 and 2001 with the BaBar detector at the PEP-II asymmetric-energy e+e- collider. No significant excess of signal events above the expected background is observed. We set a 90% C.L. limit on the branching fraction Br(B0 --> D_S+ rho-)< 1.9*10^{-5}. Assuming a flavor SU(3) symmetry relation between the decays B0 --> D_S+ rho- and B0 --> D+ rho-, we set a limit on the ratio of CKM-suppressed to CKM-favored amplitudes r(D rho)<9.5*10^{-3} at 90% C.L. All results are preliminary.