Study of $\bar B^0 \to D^0 \mu^+\mu^-$ Decay in Perturbative QCD Approach

TL;DR

This paper investigates the decay ^0 ^0 ^+^- in the Standard Model using perturbative QCD, providing predictions for the branching ratio that can be tested in current experiments to validate QCD factorization.

Contribution

It offers a perturbative QCD calculation of the ^0 ^0 ^+^- decay rate in the large recoil region, ignoring long-distance effects and subleading loops, with numerical predictions for experimental comparison.

Findings

Branching ratio ^0 ^0 ^+^- is approximately 9.7 ^{-6} in the q^2 range [1,5] GeV^2.

Branching ratio decreases rapidly with increasing q^2.

Results suggest feasibility of studying this decay channel at current B factories and LHC.

Abstract

Within the perturbative QCD approach and ignoring the contributions of long distance and subleading penguin loops, we investigate $\bar B^0 \to D^0 \mu^+\mu^-$ decay in the large recoiling kinematic region in the Standard Model. At the tree level, $\bar B^0$ decays to $D^0$ by exchanging a $W$ boson accompanied by a virtual photon emission from the valence quarks of $\bar B^0$ and $D^0$ meson, then the virtual photon decays to the lepton pair. Numerically, we find that the branching ratio decreases rapidly as the $q^2$ increases, and the branching ratio of $ \bar B^0\to D^0\mu^+\mu^-$ is $(9.7_{-3.2}^{+4.2})\times 10^{-6}$ in the region $q^2 \in [1,5] \mathrm{GeV}^2$. The order of the branching ratio shows a possibility to study this interesting channel in the current $B$ factories and the Large Hadron Collider. The precise experimental data will help us to test the factorization approach and the QCD theory, in general.