标题： 基于色散关系的|V_{cb}|非模型提取 显示英文标题

标题： Model-Independent Extraction of |V_{cb}| Using Dispersion Relations

摘要： 我们提出一种使用色散关系对重介子半轻子形式因子进行参数化的办法，并由此得出B→B弹性形式因子的两参数描述。 我们利用重夸克对称性将该函数与B→D* l \nu 形式因子相关联，并通过最小二乘拟合从实验数据中提取 |V_{cb}|=0.037^{+0.003}_{-0.002}。 我们的方法消除了在选择参数化方式以将微分衰变率外推到阈值时固有的模型依赖性不确定度。 该方法还允许以两个参数的形式准确描述B→D l nu 形式因子，精度达到1%。 显示英文摘要

摘要： We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function to B->D* l \nu form factors, and extract |V_{cb}|=0.037^{+0.003}_{-0.002} from experimental data with a least squares fit. Our method eliminates model-dependent uncertainties inherent in choosing a parametrization for the extrapolation of the differential decay rate to threshold. The method also allows a description of B -> D l nu form factors accurate to 1% in terms of two parameters.