arXiv 1909.008752019-09-02hep-ph

费米子EFT算符强抑制和保管对称破缺的简单解释

Simple explanation of strong suppression of fermionic EFT operators and custodial symmetry breaking

Adolfo Guevara, Fernando Alvarado, Juan José Sanz Cillero

备注：: 10 pages, 2 figures, Proceedings of LHCP 2019 at BUAP, Puebla, Mexico

摘要：

本方法依赖于SM手征对称性破缺模式$SU(2)_L\otimes SU(2)_R\to SU(2)_{L+R}$，其中EW Goldstone玻色子在非线性实现中给出，而希格斯玻色子由EW单线态场描述。此外，我们假设存在新的物理重态的TeV规模，不耦合到SM费米子，只有SM玻色子部门。然而，规范玻色子和BSM共振之间的混合诱导BSM扇区和SM费米子之间的小的间接相互作用。这导致了一个重要的抑制的费米子运营商在低能量EW有效理论（双线性和四费米子运营商）相比，纯玻色子的。这自然解释了费米子算符的强实验边界，以及为什么这些共振还不能被检测到：即使在现在和未来的加速器中可以达到TeV量级的能量，由于这种抑制机制，它们从初始SM费米子产生的截面非常小。另一方面，它们可以在SM玻色子测量中留下印记，供未来的实验运行使用（例如，倾斜$S$和$T$参数）。最后，我们比较我们的结果与对撞机数据的约束。

英文摘要：

The present approach relies on the SM chiral symmetry breaking pattern $SU(2)_L\otimes SU(2)_R\to SU(2)_{L+R}$, with the EW Goldstone bosons given in a non-linear realization and the Higgs boson described by an EW singlet field. In addition, we assume the presence of new physics heavy states around the TeV scale that do not couple to the SM fermions, only to the SM bosonic sector. However, the mixing between gauge bosons and BSM resonances induces a small indirect interaction between the BSM sector and the SM fermions. This leads to an important suppression of the fermionic operators in the low-energy EW effective theory (bilinear and four-fermion operators) in comparison with the purely bosonic ones. This naturally explains the strong experimental bounds on fermionic operators and why these resonances could not be yet detected: even if energies of the order of the TeV can be reached in present and future accelerators, their production from initial SM fermions yields a very small cross section because of this suppression mechanism. On the other hand, they can leave an imprint in SM boson measurements accessible to future experimental runs (e.g., the oblique $S$ and $T$ parameters). Finally, we compare our results with constraints from collider data.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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