C. N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794, USA.
Berkeley Center for Theoretical Physics, Department of Physics, University of California, Berkeley, California 94720, USA and Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2019 Feb 1;122(4):041802. doi: 10.1103/PhysRevLett.122.041802.
The commonly assumed cosmological history of our Universe is that at early times and high temperatures the Universe went through an electroweak phase transition (EWPT). Assuming an EWPT, and depending on its strength, there are many implications for baryogenesis, gravitational waves, and the evolution of the Universe in general. However, it is not true that all spontaneously broken symmetries at zero temperature are restored at high temperature. In particular the idea of "inverse symmetry breaking" has long been established in scalar theories with evidence from both perturbative and lattice calculations. In this Letter we demonstrate that with a simple extension of the standard model it is possible that the EW symmetry was always broken or only temporarily passed through a symmetry-restored phase. These novel phase histories have many cosmological and collider implications that we discuss. The model presented here serves as a useful benchmark comparison for future attempts to discern the phase of our Universe at T≳a few GeV.
通常假设的我们宇宙的宇宙学历史是，在早期和高温时，宇宙经历了一个电弱相变（EWPT）。假设存在 EWPT，并且取决于其强度，对重子生成、引力波以及宇宙的一般演化有许多影响。然而，并非所有在零温度下自发破缺的对称性在高温下都得到恢复。特别是，“逆对称破缺”的思想在标量理论中早已确立，从微扰和格点计算中都得到了证据。在这封信中，我们证明了通过对标准模型的简单扩展，电弱对称性可能始终被打破，或者只是暂时经过一个对称性恢复的阶段。这些新的相历史有许多宇宙学和对撞机的影响，我们将对此进行讨论。这里提出的模型为未来尝试辨别我们宇宙在 T≳a few GeV 时的相提供了一个有用的基准比较。
