Observation of a Near-threshold $D^0\bar{D}^0\pi^0$ Enhancement in $B \to D^0\bar{D}^0\pi^0 K$ Decay

TL;DR

This paper reports the first observation of a near-threshold enhancement in the $D^0ar{D}^0\pi^0$ system from $B$ decays, indicating a possible new resonance near 3875 MeV/$c^2$ with measured branching fraction.

Contribution

First observation of a near-threshold $D^0ar{D}^0\pi^0$ enhancement in $B$ decays using Belle data, revealing a new resonance near 3875 MeV/$c^2$.

Findings

Enhancement peaks at 3875.4 MeV/$c^2$

Branching fraction measured as approximately 1.27 x 10^{-4}

Data collected with Belle at KEKB

Abstract

We report the first observation of a near-threshold enhancement in the $D^0\bar{D}^0\pi^0$ system from $B \to D^0\bar{D}^0\pi^0 K$ decays using a 414 $\mathrm{fb}^{-1}$ data sample collected at the $\Upsilon(4S)$ resonance. The enhancement peaks at a mass $M=3875.4 \pm 0.7_{-2.0}^{+1.2}$ MeV/$c^2$ and the branching fraction for events in the peak is \Br ($B \to D^0\bar{D}^0\pi^0 K$)=(1.27 $\pm$ 0.31 $_{-0.39}^{+0.22})$ $\times$ $10^{-4}$. The data were collected with the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider.