论文标题
SMEFT中的托管对称性（违规）
Custodial Symmetry (Violation) in SMEFT
论文作者
论文摘要
我们调查了对托管对称/违反标准模型的紫外线物理敏感的精确观测值。我们使用SMEFT框架通常包括非蓝色校正，该校正需要对Peskin-Takeuchi $ t $参数进行概括，以明确检测托管对称性/违规行为。我们迈出了构建SMEFT重新竞技化不变性替代品的第一步，我们称之为$ \ Mathscr {T} $，至少对违反树木级的托管供款有效。我们利用了$ν$ smeft的新托管基础（由右手中微子增强）明确识别了Higgs和费米昂领域的全局$ su（2）_r $ symmetries，这反过来允许轻松识别具有持有或违规的高维运营商。我们仔细考虑了在一个基础上导致托管对称操作员的动作方程式冗余，等同于在另一个基础上违反一组托管对称和/或违反操作员。利用有关树/循环操作员生成的已知结果，我们证明了托管 - 侵略运算符的基础依赖性外观并不会使我们的$ \ Mathscr {t} $参数在树级别上无效。我们用几个紫外线理论示例来说明结果，表明$ \ mathscr {t} $忠实地识别了违反保管对称性的行为，而$ t $可能会失败。
We investigate precision observables sensitive to custodial symmetric/violating UV physics beyond the Standard Model. We use the SMEFT framework which in general includes non-oblique corrections that requires a generalization of the Peskin-Takeuchi $T$ parameter to unambiguously detect custodial symmetry/violation. We take a first step towards constructing a SMEFT reparameterization-invariant replacement, that we call $\mathscr{T}$, valid at least for tree-level custodial violating contributions. We utilize a new custodial basis of $ν$SMEFT (SMEFT augmented by right-handed neutrinos) which explicitly identifies the global $SU(2)_R$ symmetries of the Higgs and fermion sectors, that in turn permits easy identification of higher-dimensional operators that are custodial preserving or violating. We carefully consider equation-of-motion redundancies that cause custodial symmetric operators in one basis to be equivalent to a set of custodial symmetric and/or violating operators in another basis. Utilizing known results about tree/loop operator generation, we demonstrate that the basis-dependent appearance of custodial-violating operators does not invalidate our $\mathscr{T}$ parameter at tree-level. We illustrate our results with several UV theory examples, demonstrating that $\mathscr{T}$ faithfully identifies custodial symmetry violation, while $T$ can fail.
