文章基本信息

标题：The rho radiative decay width from lattice QCD
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作者：M.Petschlies ; C.Alexandrou ; L.Leskovec 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2018
卷号：317
DOI：10.22323/1.317.0080
语种：English
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Pion photoproduction constitutes a prototype process, which allows for the study of the electro-weak decay of a QCD-unstable state, the $\rho$ resonance. It is also the most straightforward process to investigate such ( resonant ) transition matrix elements in lattice QCD. We performed a lattice calculation of the process $\pi\pi \to \rho \to \pi\gamma$, at presently the lightest pion mass of 317 MeV and in a large box of size (3.6 fm)$^3$. In addition to outlining the method for our calculation, we give account of our analysis of systematic uncertainties, with focus on parametrization dependence of the $P-$wave phase shift and the analytic continuation of our lattice data to the $\rho$ resonance pole to extract the coupling $|G_{\rho \pi \gamma} | = 0.0802\,(38)$.