Measurement of B0->D_s(*)+D*- Branching Fractions and B0->D_s*+D*- Polarization with a Partial Reconstruction Technique

TL;DR

This paper measures specific B0 meson decay branching fractions and polarization using a partial reconstruction method, providing results consistent with theoretical expectations and demonstrating the technique's effectiveness.

Contribution

It introduces a partial reconstruction approach to measure B0 decay branching fractions and polarization, improving analysis efficiency and precision.

Findings

Branching fraction BR(B0->D_s+D*-) = (1.03 +/- 0.14 +/- 0.13 +/- 0.26)%

Branching fraction BR(B0->D_s*+D*-) = (1.97 +/- 0.15 +/- 0.30 +/- 0.49)%

Longitudinal polarization fraction = (51.9 +/- 5.0 +/- 2.8)%

Abstract

We present a study of the decays B0->D_s(*)+D*-, using 20.8 fb-1 of e+e- annihilation data recorded with the BABAR detector. The analysis is conducted with a partial reconstruction technique, in which only the D_s(*)+ and the soft pion from the D*- decay are reconstructed. We measure the branching fractions BR(B0->D_s+D*-) = (1.03 +/- 0.14 +/- 0.13 +/- 0.26)% and BR(B0->D_s*+D*-) = (1.97 +/- 0.15 +/- 0.30 +/- 0.49)%, where the first error is statistical, the second is systematic, and the third is the error due to the D_s+->phi pi+ branching fraction uncertainty. From the B0->D_s*+D*- angular distributions, we measure the fraction of longitudinal polarization Gamma_L/Gamma = (51.9 +/- 5.0 +/- 2.8)%, which is consistent with theoretical predictions based on factorization.