Catà Oscar
Fakultät für Physik, Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, 80333 Munich, Germany ; TUM-IAS, Lichtenbergstr. 2a, 85748 Garching, Germany ; Physik Department, TUM, 85748 Garching, Germany.
Eur Phys J C Part Fields. 2014;74(8):2991. doi: 10.1140/epjc/s10052-014-2991-3. Epub 2014 Aug 7.
If electroweak symmetry breaking is driven by a new strongly coupled dynamical sector, one expects the bound states to appear at the TeV scale or slightly below. However, electroweak precision data imposes severe constraints on most of the existing models, putting them under strain. Conventional models require the new composite states to come in pairs of rather heavy, close to degenerate spin-1 resonances. In this paper I argue that spin-1 states can actually be lighter without clashing with experimental bounds. As an example, I consider a composite model with a light pseudovector resonance that couples to the Standard Model gauge boson, fermion, and scalar fields. I show how such a resonance leaves basically no imprint on the NLO corrections to the Standard Model. This happens not through parameter tuning, but rather as a consequence of generic properties of realistic UV completions. This pseudovector is mostly unconstrained by existing data and could be as light as 600 GeV. In the last part of the paper I briefly discuss its most characteristic signatures for direct detection at colliders.
如果电弱对称性破缺是由一个新的强耦合动力学扇区驱动的，那么人们预期束缚态会出现在 TeV 尺度或略低于该尺度的地方。然而，电弱精确数据对大多数现有模型施加了严格的限制，使它们面临压力。传统模型要求新的复合态以一对相当重的、近乎简并的自旋为 1 的共振态形式出现。在本文中，我认为自旋为 1 的态实际上可以更轻而不会与实验限制相冲突。作为一个例子，我考虑一个具有轻赝矢量共振的复合模型，该共振与标准模型规范玻色子、费米子和标量场耦合。我展示了这样一个共振如何在对标准模型的 NLO 修正中基本上不留下印记。这不是通过参数调整发生的，而是现实紫外完备化的一般性质的结果。这个赝矢量大多不受现有数据的限制，并且可能轻至 600 GeV。在论文的最后一部分，我简要讨论了它在对撞机上直接探测的最具特征的信号。
