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All-in-one relaxion: A unified solution to five particle-physics puzzles

Gupta, R. S.; Reiness, J. Y.; Spannowsky, M.

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R. S. Gupta

J. Y. Reiness


We present a unified relaxion solution to the five major outstanding issues in particle physics: Higgs mass naturalness, dark matter, matter-antimatter asymmetry, neutrino masses and the strong CP problem. The only additional field content in our construction with respect to standard relaxion models is an up-type vectorlike fermion pair and three right-handed neutrinos charged under the relaxion shift symmetry. The observed dark matter abundance is generated automatically by oscillations of the relaxion field that begin once it is misaligned from its original stopping point after reheating. The matter-antimatter asymmetry arises from spontaneous baryogenesis induced by the CPT violation due to the rolling of the relaxion after reheating. The CPT violation is communicated to the baryons and leptons via an operator, ∂μϕJμ, where Jμ consists of right-handed neutrino currents arising naturally from a simple neutrino mass model. Finally, the strong CP problem is solved via the Nelson-Barr mechanism, i.e., by imposing CP as a symmetry of the Lagrangian that is broken only spontaneously by the relaxion. The CP breaking is such that although an Oð1Þ strong Cabibbo-Kobayashi-Maskawa (CKM) phase is generated, the induced strong CP phase is much smaller, i.e., within experimental bounds.


Gupta, R., Reiness, J., & Spannowsky, M. (2019). All-in-one relaxion: A unified solution to five particle-physics puzzles. Physical Review D, 100(5), Article 055003.

Journal Article Type Article
Online Publication Date Sep 5, 2019
Publication Date Sep 1, 2019
Deposit Date Sep 10, 2019
Publicly Available Date Sep 10, 2019
Journal Physical Review D
Print ISSN 2470-0010
Electronic ISSN 2470-0029
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 100
Issue 5
Article Number 055003


Published Journal Article (366 Kb)

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Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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