期刊
PHYSICAL REVIEW D
卷 96, 期 3, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevD.96.034020
关键词
-
资金
- U.S. National Science Foundation [PHY15-15738]
As with parton distributions, flexible phenomenological parametrizations of generalized parton distributions (GPDs) are essential for their extraction from data. The large number of constraints imposed on GPDs make simple Lorentz covariant models viable; but, such models are often incomplete in that they employ the impulse approximation. Using the GPD of the pion as a test case, we show that the impulse approximation can lead to violation of the positivity bound required of GPDs. We focus on a particular model of the pion bound-state vertex that was recently proposed and demonstrate that satisfying the bound is not guaranteed by Lorentz covariance. Violation of the positivity bound is tied to a problematic mismatch between the behavior of the quark distribution at the end point and the crossover value of the GPD.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据