2005/11/20 by Huisheng Wang, Xin Liu, Zhen-Jun Xiao +4
Mathematics · Physics and Astronomy · #Algorithm #Annihilation #Asymmetry #Branching fraction #CP violation #Electroweak interaction #Factorization #High-Energy Particle Collisions Research #Mathematics #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Perturbative QCD #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Sign (mathematics) #hep-ex #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2006.01.021
published as Nucl.Phys.B738:243-268,2006 · 28 pages, 8 figures, several typos corrected
arxiv created 2005/11/20 · openalex publication_date 2006/01/31 · arxiv updated 2009/12/01 · openalex created_date 2021/08/16 · openalex updated_date 2026/08/05
We calculate the branching ratios and CP-violating asymmetries for B0 → π0 η(′) and B+→ π+ η(′) decays in the perturbative QCD (pQCD) factorization approach here. We not only calculate the usual factorizable contributions, but also evaluate the non-factorizable and annihilation type contributions. Besides the current-current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. The pQCD results for the CP-averaged branching ratios are Br(B+ → π+ η) ≈ 4.1 × 10-6, Br(B+ → π+ η^′) ≈ 2.4 × 10-6, and Br(B0 → π0 η(′)) ≈ 0.2 × 10-6, which agree very well with the measured values or currently available experimental upper limits. We also predict large CP-violating asymmetries in these decays: ACPdir(π^± \etap)∼ ACPdir(π0 \etap)∼ -0.35 , and ACPmix(π0 \etap)∼ 0.67, but with large errors. The pQCD prediction for ACPdir(π^± η) (ACPdir(π^± η^′)) has the same (opposite) sign with the primary measured values. Further improvements in both theory and experiments are needed to clarify this discrepancy.