论文标题
侵犯最小风味的阳性范围
Positivity bounds on Minimal Flavor Violation
论文作者
论文摘要
从对紫外线理论的一般分析性和单位性要求中,最近得出了由4个费米亚组成的维尔逊系数的阳性界限,最近在标准模型有效场理论中出现了两个衍生物。我们在具有最小的风味(MFV)结构的模型的背景下探索了这些界限的命运,其中模型中较高维操作员的风味结构是从已经包含的标准模型Lagrangian的Yukawa扇区中所包含的模型。我们的目标是检查一般阳性界限是否转化为Yukawa系数和/或CKM矩阵元素上的边界。 MFV将Dimension-8运算符的系数固定到一些乘法风味盲因素上,我们发现,在最通用的设置中,这些未指定系数留下的自由足以限制可降级的Yukawa部门的参数。相反,后者塑造了前者允许的区域。要求所述总系数采取天然$ \ MATHCAL {O}(1)$值可能会导致Yukawa耦合的界限。值得注意的是,在Yukawa矩阵力量扩展的领先秩序中,CKM条目上没有界限。
From general analyticity and unitarity requirements on the UV theory, positivity bounds on the Wilson coefficients of the dimension-8 operators composed of 4 fermions and two derivatives appearing in the Standard Model Effective Field Theory have been derived recently. We explore the fate of these bounds in the context of models endowed with a Minimal Flavor Violation (MFV) structure, models in which the flavor structure of higher dimensional operators is inherited from the one already contained in the Yukawa sector of the Standard Model Lagrangian. Our goal is to check whether the general positivity bounds translate onto bounds on the Yukawa coefficients and/or on elements of the CKM matrix. MFV fixes the coefficients of dimension-8 operators up to some multiplicative flavor-blind factors and we find that, in the most generic setup, the freedom left by those unspecified coefficients is enough as not to constrain the parameters of the renormalizable Yukawa sector. On the contrary, the latter shape the allowed region for the former. Requiring said overall coefficients to take natural $\mathcal{O}(1)$ values could give rise to bounds on the Yukawa couplings. Remarkably, at leading order in an expansion in powers of the Yukawa matrices, no bounds on the CKM entries can be retrieved.