Chiral Nelson-Barr models: Quality and cosmology
It was recently shown that domain walls from the spontaneous breaking of CP symmetry are exactly stable, and must be inflated away to recover a viable cosmology. We investigate the phenomenological implications of this result in Nelson-Barr solutions of the strong CP problem. Combined with the upper...
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Veröffentlicht in: | Physical review. D 2023-06, Vol.107 (11), Article 115012 |
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Sprache: | eng |
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Zusammenfassung: | It was recently shown that domain walls from the spontaneous breaking of CP symmetry are exactly stable, and must be inflated away to recover a viable cosmology. We investigate the phenomenological implications of this result in Nelson-Barr solutions of the strong CP problem. Combined with the upper bound on the scale of spontaneous CP breaking necessary to suppress contributions from dangerous, nonrenormalizable operators to $\overline{\theta}$ , this puts an upper bound on the scale of inflation and the reheating temperature after inflation. Minimal Nelson-Barr models are therefore in tension with thermal leptogenesis, models of large-field inflation, or potential future observations of signals from topological remnants of an unrelated, subsequent phase transition. We study how extending Nelson-Barr models with a new, continuous chiral gauge symmetry can ameliorate this tension by forbidding the dangerous dimension-five operators. In particular, we show that gauging a linear combination of baryon number and hypercharge allows for an economic, anomaly-free extension of the minimal Nelson-Barr model, and discuss the phenomenological implications. |
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ISSN: | 2470-0010 2470-0029 |
DOI: | 10.1103/PhysRevD.107.115012 |