标题： 奇异介子和重子半轻子衰变中SU(3)破缺效应的格点QCD研究 显示英文标题

标题： SU(3)-breaking effects in kaon and hyperon semileptonic decays from lattice QCD

摘要： 我们讨论了最近在零动量转移下K→π矢量形式因子的淬火格点计算结果，这对于从K→πlν衰变中确定|V_us|是相关的。 通过使用三个点关联函数的适当双重比值，我们表明可以在百分之一精度水平上计算这个量。 通过淬火手征微扰理论修正了主要的淬火效应。 最终结果f+(0)=0.960±0.005_统计±0.007_系统，与Leutwyler和Roos以前的夸克模型估计相符。 在本文中，我们通过用最新的实验数据更新K→πlν衰变的分析，讨论了格点结果对提取|V_us|的物理影响。 我们还基于类似策略，提出了对超子Σ→n l ν衰变的初步格点研究。 显示英文摘要

摘要： We discuss the result of a recent quenched lattice calculation of the K -> pi vector form factor at zero-momentum transfer, relevant for the determination of |V_us| from K-> pi l nu decays. Using suitable double ratios of three-point correlation functions, we show that it is possible to calculate this quantity at the percent-level precision. The leading quenched effects are corrected for by means of quenched chiral perturbation theory. The final result, f+(0) = 0.960 +- 0.005_stat +- 0.007_syst, turns out to be in good agreement with the old quark model estimate made by Leutwyler and Roos. In this paper, we discuss the phenomenological impact of the lattice result for the extraction of |V_us|, by updating the analysis of K -> pi l nu decays with the most recent experimental data. We also present a preliminary lattice study of hyperon Sigma -> n l nu decays, based on a similar strategy.