Study of $D^{**}$ production and light hadronic states in the $\bar{B}^0 \to D^{*+} \omega \pi^-$ decay

TL;DR

This paper reports the first observations of specific B meson decays involving excited D states and light hadronic states, providing measurements of branching fractions, polarization, and phase information from a large data sample at Belle.

Contribution

It presents the first measurements of certain $ar{B}^0$ decay modes involving $D^{**}$ and light hadronic states, including polarization and phase analyses, expanding understanding of B meson decay dynamics.

Findings

First observation of $ar{B}^0$ decays to $D_1(2430)^0 \, ext{and} \, D_1(2420)^0 \, ext{with} \, ar{B}^0 o D^{*+} \, ext{and} \, ar{B}^0 o D_2^*(2460)^0$

Measurement of branching fractions and polarization fractions for these decay modes

Evidence of nontrivial final-state interaction phases in $ ho$-like amplitudes.

Abstract

We report on the first observations of $\bar{B}^0 \to D_1(2430)^0 \omega$, $\bar{B}^0 \to D_1(2420)^0 \omega$ and $\bar{B}^0 \to D^*_2(2460)^0 \omega$ decays. The $\bar{B}^0 \to D^{*+} \rho(1450)^-$ decay is also observed. The branching fraction measurements are based on $(771.6 \pm 10.6)\times 10^6$ $B\bar{B}$ events collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The fractions of longitudinal polarization of the $D^{**}$ states as well as partial wave fractions of the $D_1(2430)^0$ are obtained. We also set a $90\%$ confidence level upper limit for the product of branching fractions of $\mathcal{B}(\bar{B}^0 \to D^{*+} b_1(1235)^-) \times \mathcal{B}(b_1(1235)^- \to \omega \pi^-)$. The measurements show evidence of nontrivial final-state interaction phases for the $\rho$-like amplitudes.