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arXiv 2012.15074hep-ph
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用微扰QCD方法研究强子两体B衰变

Global Analysis of hadronic two-body B decays in the perturbative QCD approach

Jun Hua, Hsiang-nan Li, Cai-Dian Lu, Wei Wang, Zhi-Peng Xing

摘要:

基于四夸克有效算符的味结构,我们开发了一个计算强子二体$B$介子衰变振幅的自动计算程序,并将其应用于微扰QCD(PQCD)方法的整体分析.将强耦合$α_s$中首级$B\to PP,VP$衰变的PQCD因子分解公式拟合到测量的分支比和直接CP不对称性,确定了轻介子光锥分布振幅(LCDAs)的Gegenbauer矩.结果表明,赝标介子$P$($P=π$,$K$)和矢量介子$V$($V=ρ$,$K^*$)的扭转2和扭转3 LCDAs的Gegenbauer矩与QCD求和规则的结果基本一致.还得到了$B_s$介子分布振幅和弱相$ϕ_3(γ)=(75.1\pm2.9)^\circ$的形状参数,与粒子数据组的数值一致。我们的分析可以直接扩展到高阶和更高次幂的PQCD方法,以及其他强子的LCDA的整体确定。

英文摘要:

Based on the flavor structure of four-quark effective operators, we develop an automatic computation program to calculate hadronic two-body $B$ meson decay amplitudes, and apply it to their global analysis in the perturbative QCD (PQCD) approach. Fitting the PQCD factorization formulas for $B\to PP,VP$ decays at leading order in the strong coupling $α_s$ to measured branching ratios and direct CP asymmetries, we determine the Gegenbauer moments in light meson light-cone distribution amplitudes (LCDAs). It is found that most of the fitted Gegenbauer moments of the twist-2 and twist-3 LCDAs for the pseudoscalar meson $P$ ($P=π$, $K$) and vector meson $V$ ($V=ρ$, $K^*$) agree with those derived in QCD sum rules. The shape parameter for the $B_s$ meson distribution amplitude and the weak phase $ϕ_3(γ)=(75.1\pm2.9)^\circ$ consistent with the value in Particle Data Group are also obtained. It is straightforward to extend our analysis to higher orders and higher powers in the PQCD approach, and to the global determination of LCDAs for other hadrons.

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