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Interplay between neutrino and gravity portals for FIMP dark matter

Interplay between neutrino and gravity portals for FIMP dark matter
Interplay between neutrino and gravity portals for FIMP dark matter

In the classic type I seesaw mechanism with very heavy right-handed (RH) neutrinos, it is possible to account for dark matter via RH neutrino portal couplings to a feebly interacting massive particle (FIMP) dark sector. However, for large RH neutrino masses, gravity can play an important role. We study the interplay between the neutrino portal through the right-handed neutrinos and the gravity portal through the massless spin-2 graviton in producing dark matter particles in the early universe. As a concrete example, we consider the minimal and realistic Littlest Seesaw model with two RH neutrinos, augmented with a dark scalar and a dark fermion charged under a global U(1) D dark symmetry. In the model, the usual seesaw neutrino Yukawa couplings and the right-handed neutrino masses (the lightest being about 5×10 10 GeV) are fixed by neutrino oscillations data and leptogenesis. Hence, we explore the parameter space of the two RH neutrino portal couplings, the two dark particle masses and the reheating temperature of the universe, where the correct dark matter relic abundance is achieved through the freeze-in mechanism. In particular, we highlight which class of processes dominate the dark matter production. We find that, despite the presence of the gravity portal, the dark matter production relies on the usual seesaw neutrino Yukawa coupling in some regions of the parameter space, so realising a direct link between dark matter and neutrino phenomenology. Finally, we report the threshold values for the neutrino portal couplings below which the neutrino portal is irrelevant and the Planckian Interacting Dark Matter paradigm is preserved.

hep-ph
Chianese, Marco
73113e4b-5eb5-4cdc-831b-90f4678588d6
Fu, Bowen
71c18b27-d30a-4e33-806b-e45ea5446e46
King, Stephen F.
f8c616b7-0336-4046-a943-700af83a1538
Chianese, Marco
73113e4b-5eb5-4cdc-831b-90f4678588d6
Fu, Bowen
71c18b27-d30a-4e33-806b-e45ea5446e46
King, Stephen F.
f8c616b7-0336-4046-a943-700af83a1538

Chianese, Marco, Fu, Bowen and King, Stephen F. (2021) Interplay between neutrino and gravity portals for FIMP dark matter. JCAP, 2021 (1), [034]. (doi:10.1088/1475-7516/2021/01/034).

Record type: Article

Abstract

In the classic type I seesaw mechanism with very heavy right-handed (RH) neutrinos, it is possible to account for dark matter via RH neutrino portal couplings to a feebly interacting massive particle (FIMP) dark sector. However, for large RH neutrino masses, gravity can play an important role. We study the interplay between the neutrino portal through the right-handed neutrinos and the gravity portal through the massless spin-2 graviton in producing dark matter particles in the early universe. As a concrete example, we consider the minimal and realistic Littlest Seesaw model with two RH neutrinos, augmented with a dark scalar and a dark fermion charged under a global U(1) D dark symmetry. In the model, the usual seesaw neutrino Yukawa couplings and the right-handed neutrino masses (the lightest being about 5×10 10 GeV) are fixed by neutrino oscillations data and leptogenesis. Hence, we explore the parameter space of the two RH neutrino portal couplings, the two dark particle masses and the reheating temperature of the universe, where the correct dark matter relic abundance is achieved through the freeze-in mechanism. In particular, we highlight which class of processes dominate the dark matter production. We find that, despite the presence of the gravity portal, the dark matter production relies on the usual seesaw neutrino Yukawa coupling in some regions of the parameter space, so realising a direct link between dark matter and neutrino phenomenology. Finally, we report the threshold values for the neutrino portal couplings below which the neutrino portal is irrelevant and the Planckian Interacting Dark Matter paradigm is preserved.

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2009.01847v2 - Accepted Manuscript
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Submitted date: 15 September 2020
Accepted/In Press date: 26 October 2020
Published date: 20 January 2021
Additional Information: Funding Information: BF acknowledges the Chinese Scholarship Council (CSC) Grant No. 201809210011 under agreements [2018]3101 and [2019]536. SFK acknowledges the STFC Consolidated Grant ST/L000296/1 and the European Union’s Horizon 2020 Research and Innovation programme under Marie Sk lodowska-Curie grant agreements Elusives ITN No. 674896 and InvisiblesPlus RISE No. 690575. Funding Information: BF acknowledges the Chinese Scholarship Council (CSC) Grant No. 201809210011 under agreements [2018]3101 and [2019]536. SFK acknowledges the STFC Consolidated Grant ST/L000296/1 and the European Union's Horizon 2020 Research and Innovation programme under Marie Sk?odowska-Curie grant agreements Elusives ITN No. 674896 and InvisiblesPlus RISE No. 690575. Publisher Copyright: © 2021 IOP Publishing Ltd and Sissa Medialab
Keywords: hep-ph

Identifiers

Local EPrints ID: 447365
URI: http://eprints.soton.ac.uk/id/eprint/447365
PURE UUID: 80c7a25d-21fb-4dfe-b9cd-6ef9ae836d71
ORCID for Bowen Fu: ORCID iD orcid.org/0000-0003-2270-8352

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Date deposited: 10 Mar 2021 17:35
Last modified: 17 Mar 2024 06:23

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Contributors

Author: Marco Chianese
Author: Bowen Fu ORCID iD
Author: Stephen F. King

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