Minimal seesaw extension for neutrino mass and mixing, leptogenesis and dark matter: FIMPzillas through the right-handed neutrino portal

Abstract

We propose a minimal seesaw extension to simultaneously account for realistic neutrino mass and mixing, the baryon asymmetry of the Universe via leptogenesis and a viable dark matter relic density, in which two right-handed neutrinos are coupled to a dark Dirac fermion and complex scalar field, both charged under a global U (1)D symmetry. As a concrete example, we consider the Littlest Seesaw model which describes neutrino mass and mixing and accounts for leptogenesis, thereby fixing the neutrino Yukawa couplings and right-handed neutrino masses. By considering the freezein production mechanism of dark matter, we explore the parameter space of right-handed neutrino portal couplings and dark particle masses which give the correct dark matter relic abundance, focussing on the case of a superheavy Dirac fermion dark matter particle, with a mass around 10 10 GeV. Such a FIMPzilla can provide a successful explanation of the dark matter relic abundance, with its production reliant on neutrino Yukawa couplings over much of the parameter space, depending on the assumed dark particle masses, and the reheat temperature. CONTENTS

Relativistic freeze-in with scalar dark matter in a gauged B − L model and electroweak symmetry breaking

“…In this context some studies have been pursued [9,27,29,30], where B −L gauge boson still contributes in the freeze-in production of the dark matter. The fermion plus scalar dark matter freeze-in scenarios are also explored [31][32][33].…”

Freeze-in dark matter from secret neutrino interactions

“…cific, we consider a hidden sector consisting of a dark scalar mediator φ and a fermionic dark matter χ, and the hidden sector is only connected to the SM via a neutrino portal. Typically, there are two kinds of neutrino-portal dark-matter models -the t-channel models with the ν − χ − φ interaction [20][21][22][23][24][25][26][27][28][29][30][31][32][33], and the s-channel models with the ν − ν − φ interaction [34,35], in the freeze-out scenarios. While the t-channel models have been investigated in details in recent years, in this paper, we consider the s-channel models in which the dark matter χ only interacts with the SM neutrinos through an s-channel exchange of φ in the freeze-in regime.…”

Dark matter in the type Ib seesaw model

“…The relation between these intriguing phenomena has been investigated in many works . One of the interesting possibilities is to connect the dark sector and the Standard Model through the RH neutrinos that realise the type I seesaw, which is usually named the neutrino portal scenario [104][105][106][107][108][109][110][111][112][113][114]. Some recent research [104][105][106] shows that dark matter particles can be dominantly produced through the neutrino Yukawa interactions in the seesaw sector non-thermally by the so-called "freeze-in" mechanism [115,116].…”

“…One of the interesting possibilities is to connect the dark sector and the Standard Model through the RH neutrinos that realise the type I seesaw, which is usually named the neutrino portal scenario [104][105][106][107][108][109][110][111][112][113][114]. Some recent research [104][105][106] shows that dark matter particles can be dominantly produced through the neutrino Yukawa interactions in the seesaw sector non-thermally by the so-called "freeze-in" mechanism [115,116]. In those studies, the classical type I seesaw model is adopted and the right-handed neutrinos are superheavy in order to realise the leptogenesis [117], which makes such a model hard to be constrained and tested by the relevant experiments [118][119][120][121][122][123][124][125].…”