Charged scalar portal dark matter with $U(1)_Y$ non-restoration and gravitational waves

We explore the possibility of reviving scalar singlet dark matter (DM) with a minimal extension by a charged singlet scalar which also leads to hypercharge non-restoration in the early Universe. The minimal scalar singlet DM annihilating via the Higgs portal is tightly constrained by direct-detection experiments, leaving a desert between two narrow regions of the DM mass near the Higgs resonance and around a TeV. The addition of a charged scalar portal revives this desert region while keeping the one-loop direct-detection rate within reach of current and future experiments. A non-zero vacuum expectation value of the charged scalar at high temperature can also drive $U(1)_Y$ hypercharge symmetry non-restoration in the early Universe. In a subset of the parameter space, the charge-breaking minimum gets restored to the standard Higgs minimum via a strong first-order phase transition, making it a viable scenario for the generation of baryon asymmetry of the Universe via leptogenesis. A large part of the parameter space consistent with DM relic, direct-detection, symmetry non-restoration and other experimental bounds can be probed at upcoming GW detectors such as LISA, BBO and DECIGO.

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Authors

Debasish Borah; Dhruv Ringe; Indrajit Saha

Published

Sep 30, 2026

Paper type

preprint

Source

Arxiv