Baryogenesis from spontaneous CP violation in the early Universe

Abstract

We propose a variant of electroweak-scale baryogenesis characterized by the spontaneous breaking of the charge-parity (CP) symmetry in the early Universe driven by the vacuum expectation value of a CP-odd scalar. This CP breaking period in the early Universe would be ended by the electroweak phase transition, with CP being (approximately) conserved at present, thus avoiding the stringent electric dipole moment experimental constraints on beyond-the-Standard-Model sources of CP violation. We study an explicit realization via a non-minimal Higgs sector consisting of two Higgs doublets and a singlet pseudoscalar (2HDM + $a$). We analyze the region of the 2HDM + $a$ parameter space where such an early Universe period of CP violation occurs, and show that the required thermal history and successful baryogenesis lead to a predictive scenario, testable by a combination of LHC searches and low-energy flavour measurements.

8 pages, 4 Figures, many baryons

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Cited by in corpus (4)

• The Waning of the WIMP: Endgame?
• Benchmarking a fading window: electroweak baryogenesis in the C2HDM, LHC constraints after Run 2 and prospects for LISA
• A new LHC search for dark matter produced via heavy Higgs bosons using simplified models
• Early Universe hypercharge breaking and neutrino mass generation