Revisiting the $B^{0} \to \pi^{0}\pi^{0} $ decays in the perturbative QCD approach

TL;DR

This paper recalculates the branching ratio and CP asymmetries for B0 to pi0 pi0 decays using perturbative QCD, including all diagram contributions, and finds results consistent with recent experiments, predicting large CP asymmetries for future tests.

Contribution

It provides a comprehensive recalculation of B0 to pi0 pi0 decay observables in perturbative QCD, considering all diagram types, and offers predictions for CP asymmetries for upcoming experiments.

Findings

Branching ratio: (1.17_{-0.12}^{+0.11})×10^{-6}

Results agree with Belle and HFAG measurements

Predicts large direct and mixing CP asymmetries

Abstract

We recalculate the branching ratio and CP asymmetry for $\bar{B}^{0} (B^{0})\to \pi^{0}\pi^{0}$ decays in the Perturbative QCD approach. In this approach, we consider all the possible diagrams including non-factorizable contributions and annihilation contributions. We obtain $Br(\bar{B}^{0} (B^{0})\to \pi^{0}\pi^{0})=(1.17_{-0.12}^{+0.11})\times 10^{-6}$. Our result is in agreement with the latest measured branching ratio of $B^{0}\to\pi^{0}\pi^{0}$ by the Belle and HFAG Collaborations. We also predict large direct CP asymmetry and mixing CP asymmetry in $B^{0}\to\pi^{0}\pi^{0}$ decays, which can be tested by the coming Belle-II experiments.