文章基本信息

标题：Dispersive construction of two-loop P->3pi (P=K,eta) amplitudes
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作者：M. ZDRAHAL ; K. KAMPF ; M. Knecht 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2009
卷号：2009
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The branching ratio of the h →3p decay is an important source of information on the value of the quark mass ratio 1R = md−mu ms−bm . Furthermore, isospin breaking effects in the decays K→3p provide information on the pion scattering lengths. The cusp effect in the K → 3p decays is presently being analyzed by the NA48 and KTeV experiments. From the theoretical point of view, these processes have been studied by different methods. We propose a unified and relativistic treatment relying on very general principles, unitarity, analyticity and crossing symmetry, combined with chiral counting, in order to construct model-independent representations of the corresponding amplitudes that are valid at two loops. A general description of the procedure is given and is illustrated in the case of the h decay amplitude in the leading order in the isospin breaking.