$B \to (\jpsi,\eta_c) K$ decays in the perturbative QCD approach

TL;DR

This paper calculates branching ratios and CP asymmetries for B to J/psi and eta_c K decays using perturbative QCD with partial NLO corrections, finding predictions close to experimental data and confirming CP asymmetry measurements.

Contribution

The study incorporates partial NLO contributions into pQCD calculations of B decays, improving theoretical predictions and agreement with experimental results.

Findings

NLO pQCD predictions are about 40% smaller than measured branching ratios but within 2-sigma errors.

Predicted CP asymmetries match experimental data.

Branching ratios are consistent with observations within uncertainties.

Abstract

In this paper, we calculated the $B \to (\jpsi, \eta_c) K$ decays in the perturbative QCD approach with the inclusion of the partial next-to-leading order (NLO) contributions. We found that (a) when the large enhancements from the known NLO contributions are taken into account, the NLO pQCD predictions for the branching ratios are the following: $Br(B^0 \to \jpsi K^0) = 5.2^{+3.5}_{-2.8}\times 10^{-4}$, $Br(B^+ \to \jpsi K^+) = 5.6^{+3.7}_{-2.9}\times 10^{-4}$, $Br(B^0 \to \eta_c K^0) = 5.5^{+2.3}_{-2.0}\times 10^{-4}$, $Br(B^+ \to \eta_c K^+) = 5.9^{+2.5}_{-2.1}\times 10^{-4}$, which are roughly 40% smaller than the measured values, but basically agree with the data within $2-\sigma$ errors; (b) the NLO pQCD predictions for the CP-violating asymmetries of $B \to (\jpsi,\eta_c)K$ decays agree perfectly with the data.