Physicists Propose New Mechanism for Eliminating Cosmic Domain Walls in Beyond-Standard-Model Theories
Researchers have proposed a new annihilation mechanism for multi-wall string topological configurations that arise in particle physics models with global U(1) symmetries broken by gravitational effects. The so-called cosmological domain wall problem occurs when networks of domain walls attached to cosmic strings scale too slowly and risk dominating the Universe's energy density, conflicting with Big Bang Nucleosynthesis constraints. The proposed solution — using temperature-dependent radiative corrections generated by small bare mass terms of fermions — could resolve this long-standing cosmological tension within majoron frameworks involving right-handed neutrinos.
A new preprint submitted to arXiv presents a theoretical mechanism for eliminating cosmologically problematic domain wall (DW) networks that form in models extending the Standard Model via global U(1) symmetries. Such symmetries are widely expected to be explicitly violated by gravitational effects near the Planck scale, which can reduce U(1) to a discrete subgroup and seed the formation of cosmic strings bound to multiple domain walls. These wall-string networks are dangerous because their energy density scales too slowly, potentially coming to dominate the Universe and conflicting with tight constraints from Big Bang Nucleosynthesis. The authors show that if a fermion coupled to the symmetry-breaking scalar carries a small bare mass term, radiative corrections generate a temperature-dependent energy bias between competing vacua, which can trigger the annihilation of the DW network before it becomes cosmologically dominant. As a concrete example, the paper applies this mechanism to a majoron model featuring right-handed neutrinos with small bare masses, demonstrating that these masses naturally supply the required bias. The work spans 8 pages with 3 figures and 1 table, and is affiliated with HRI-RECAPP. It has not yet undergone peer review.
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- arXiv astro-phCenter
A New Route to the Annihilation of Multi-Wall String Topological Configurations
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