Crescendo beyond the horizon: More gravitational waves from domain walls bounded by inflated cosmic strings

Journal Article · 06 November 2024 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/jhep11(2024)032 · OSTI ID:2481505

Bao, Yunjia  ^[1]; Harigaya, Keisuke  ^[2]; Wang, Lian-Tao  ^[1]

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1. University of Chicago, IL (United States)
2. University of Chicago, IL (United States); University of Tokyo, Chiba (Japan)

Gravitational-wave (GW) signals offer a unique window into the dynamics of the early universe. GWs may be generated by the topological defects produced in the early universe, which contain information on the symmetry of UV physics. We consider the case in which a two-step phase transition produces a network of domain walls bounded by cosmic strings. Specifically, we focus on the case in which there is a hierarchy in the symmetry-breaking scales, and a period of inflation pushes the cosmic string generated in the first phase transition outside the horizon before the second phase transition. We show that the GW signal from the evolution and collapse of this string-wall network has a unique spectrum, and the resulting signal strength can be sizeable. In particular, depending on the model parameters, the resulting signal can show up in a broad range of frequencies and can be discovered by a multitude of future probes, including the pulsar timing arrays and space- and ground-based GW observatories. As an example that naturally gives rise to this scenario, we present a model with the first phase transition followed by a brief period of thermal inflation driven by the field responsible for the second stage of symmetry breaking. Here, the model can be embedded into a supersymmetric setup, which provides a natural realization of this scenario. In this case, the successful detection of the peak of the GW spectrum probes the soft supersymmetry breaking scale and the wall tension.

• Research Organization: University of Chicago, IL (United States)
• Sponsoring Organization: Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT); USDOE Office of Science (SC); USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0009924; SC0013642; SC0025242
• OSTI ID: 2481505
• Journal Information: Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 11 Vol. 2024; ISSN 1029-8479
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English