标题： 自发对称性破缺，规范层次和电弱真空亚稳定性 显示英文标题

标题： Spontaneous symmetry breaking, gauge hierarchy and electroweak vacuum metastability

摘要： 所谓的亚稳性界限表明，一个异常小的希格斯粒子质量是电弱真空亚稳性的必要条件，为解决层次问题提供了一种新方法。 到目前为止，这一结果依赖于负的希格斯质量参数假设，或者等价地，依赖于电弱自发对称性破缺。 我们推导出了正质量参数情况下的新对应界限。 当新界限比已建立的界限更严格或相当，则可能解释希格斯质量参数的符号，从而解释自发对称性破缺本身。 在$\mathcal{O} (1-10)$ TeV尺度的新物理可以将这些界限降低到TeV尺度。 作为例证，我们考虑了在具有与希格斯耦合的额外TeV尺度费米子以及参数化紫外区新物理的六维项的情况下真空稳定性。 此情景需要与希格斯强烈耦合的新物理，并可能在未来的对撞机上被探测。 最后，为了与预测亚稳性的具体机制进行比较，我们提供了该模型中电弱真空的质量依赖寿命。 显示英文摘要

摘要： The so-called metastability bound asserts that an unnaturally small Higgs mass is a necessary condition for electroweak vacuum metastability, offering a new approach towards solving the hierarchy problem. So far, this result relies on the assumption of a negative Higgs mass parameter, or equivalently, on electroweak spontaneous symmetry breaking. We derive a new, corresponding bound for the case of a positive mass parameter. When the new bound is significantly more restrictive than or comparable to its established counterpart, it may offer an explanation for the sign of the Higgs mass parameter, and thus, spontaneous symmetry breaking itself. New physics at scales $\mathcal{O} (1-10)$ TeV can lower these bounds as far as the TeV-scale. As an illustration, we consider vacuum stability in the presence of additional TeV-scale fermions with Yukawa couplings to the Higgs, as well as a dimension-six term parameterizing new physics in the UV. This scenario requires new physics that couples strongly to the Higgs, and can potentially be probed at future colliders. Finally, to allow for comparison with concrete mechanisms predicting metastability, we provide the mass-dependent lifetime of the electroweak vacuum for this model.