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The dark side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas

The dark side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas
The dark side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas
We propose a minimal model to simultaneously account for a realistic neutrino spectrum through a type-I seesaw mechanism and a viable dark matter relic density. The model is an extension of the Littlest Seesaw model in which the two right-handed neutrinos of the model are coupled to a Z2-odd dark sector via right-handed neutrino portal couplings. In this model, a highly constrained and direct link between dark matter and neutrino physics is achieved by considering the freeze-in production mechanism of dark matter. We show that the neutrino Yukawa couplings which describe neutrino mass and mixing may also play a dominant role in the dark matter production. We investigate the allowed regions in the parameter space of the model that provide the correct neutrino masses and mixing and simultaneously give the correct dark matter relic abundance. In certain cases the right-handed neutrino mass may be arbitrarily large, for example in the range 1010–1011 GeV required for vanilla leptogenesis, with a successful relic density arising from frozen-in dark matter particles with masses around this scale, which we refer to as "fimpzillas".
1475-7516
Chianese, Marco
73113e4b-5eb5-4cdc-831b-90f4678588d6
King, Stephen
f8c616b7-0336-4046-a943-700af83a1538
Chianese, Marco
73113e4b-5eb5-4cdc-831b-90f4678588d6
King, Stephen
f8c616b7-0336-4046-a943-700af83a1538

Chianese, Marco and King, Stephen (2018) The dark side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas. Journal of Cosmology and Astroparticle Physics, [027]. (doi:10.1088/1475-7516/2018/09/027).

Record type: Article

Abstract

We propose a minimal model to simultaneously account for a realistic neutrino spectrum through a type-I seesaw mechanism and a viable dark matter relic density. The model is an extension of the Littlest Seesaw model in which the two right-handed neutrinos of the model are coupled to a Z2-odd dark sector via right-handed neutrino portal couplings. In this model, a highly constrained and direct link between dark matter and neutrino physics is achieved by considering the freeze-in production mechanism of dark matter. We show that the neutrino Yukawa couplings which describe neutrino mass and mixing may also play a dominant role in the dark matter production. We investigate the allowed regions in the parameter space of the model that provide the correct neutrino masses and mixing and simultaneously give the correct dark matter relic abundance. In certain cases the right-handed neutrino mass may be arbitrarily large, for example in the range 1010–1011 GeV required for vanilla leptogenesis, with a successful relic density arising from frozen-in dark matter particles with masses around this scale, which we refer to as "fimpzillas".

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The dark side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas - Accepted Manuscript
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Accepted/In Press date: 6 September 2018
e-pub ahead of print date: 17 September 2018

Identifiers

Local EPrints ID: 425536
URI: http://eprints.soton.ac.uk/id/eprint/425536
ISSN: 1475-7516
PURE UUID: 725d9096-a3d2-464c-8751-eb0a0abd5f52

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Date deposited: 24 Oct 2018 16:30
Last modified: 03 Mar 2021 05:01

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Author: Marco Chianese
Author: Stephen King

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