Studies of $B^0 \to \rho^\pm \pi^\mp$ and Evidence of $B^0 \to \rho^0 \pi^0$

TL;DR

This study measures branching fractions and charge asymmetry for $B^0$ decays to rho and pion states, providing the first evidence for the $B^0 o ho^0 o ho^0 o ho^0$ decay with significant statistical support.

Contribution

It reports the first evidence for $B^0 o ho^0 o ho^0 o ho^0$ decay and provides precise measurements of branching fractions and asymmetries for $B^0 o ho^ pm o ho^ pm$ decays.

Findings

Branching fraction for $B^0 o ho^ pm o ho^ pm$ is approximately 29.1 x 10^{-6}.

First evidence (3.1 sigma) for $B^0 o ho^0 o ho^0 o ho^0$ decay.

Charge asymmetry for $B^0 o ho^ pm o ho^ pm$ is about -0.38.

Abstract

We report studies of $B^0 \to \pi^+ \pi^- \pi^0$, using $78 {\rm fb}^{-1}$ of data collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric $e^+e^-$ storage ring. We measure the branching fraction for $B^0 \to \rho^\pm \pi^\mp$ to be ${\mathcal B}(B^0 \to \rho^\pm \pi^\mp) = (29.1 ^{+5.0}_{-4.9}({\rm stat}) \pm 4.0({\rm syst})) \times 10^{-6}$, and find an untagged charge asymmetry ${\mathcal A} = -0.38^{+0.19}_{-0.21} ({\rm stat}) ^{+0.04}_{-0.05} ({\rm syst})$. We find the first evidence for $B^0 \to \rho^0 \pi^0$ with $3.1\sigma$ statistical significance and with a branching fraction of ${\mathcal B}(B^0 \to \rho^0\pi^0) = (6.0 ^{+2.9}_{-2.3} ({\rm stat}) \pm 1.2 ({\rm syst})) \times 10^{-6}$.