Charge asymmetry in decays $ B\rightarrow D\bar DK$

TL;DR

This paper investigates charge asymmetry in B meson decays to D meson pairs near the Psi(3770) resonance, revealing differences from e+e- annihilation and proposing a model based on isospin interference to explain the observations.

Contribution

It introduces a simple interference model of isoscalar and isovector amplitudes to explain charge asymmetries in B decays near the Psi(3770) resonance.

Findings

In B+ decays, D0 D̄0 production is nearly three times more likely than D+ D−.

In B0 decays, the ratio of D0 D̄0 to D+ D− production is reversed.

The model successfully explains the observed charge asymmetry data.

Abstract

We discusses the charge asymmetry in $ B\rightarrow D\bar DK$ decays with an invariant mass of the $D\bar D$ pair near the $\Psi(3770)$ resonance. Unlike $ \Psi (3770) $ decays in $ e^+e^- $ annihilation, in $B^+$ decays the probability of $D^0\bar D^0$ production is almost three times higher than $D^+ D^-$. In $B^0$ decays, the ratio of these probabilities will be opposite. The effect is explained by the fact that, in $B$ -meson decays, the $D\bar D$ pair is produced in a superposition of isoscalar and isovector states, and only in combination with $K$ -mesons the total state has $ 1/2 $ isospin. We present a simple model in which the interference of the nonresonant isovector amplitude with the resonant isoscalar amplitude explains the experimental data.