Fitting high-energy Littlest Seesaw parameters using low-energy neutrino data and leptogenesis

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

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“…Hence, according to Ref. [26], we take the following benchmark values for the right-handed neutrino Majorana masses M 1 = 5.10 × 10 10 GeV and…”

Section: The Modelmentioning

confidence: 99%

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

Chianese

King

2020

J. Cosmol. Astropart. Phys.

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“…where J k L +k E (γ f , τ f ) = J k L +k E (γ 0 , τ 0 ) and J 2k L (γ f , τ f ) = J 2k L (γ 0 , τ 0 ) are certain phase factors 3 , as shown in Eq. (55). From Eq.…”

Section: Residual Modular Symmetry and Its Implicationmentioning

confidence: 99%

Modular S4 and A4 symmetries and their fixed points: new predictive examples of lepton mixing

Ding

King

Liu

et al. 2019

J. High Energ. Phys.

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125

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In the modular symmetry approach to neutrino models, the flavour symmetry emerges as a finite subgroup Γ N of the modular symmetry, broken by the vacuum expectation value (VEV) of a modulus field τ . If the VEV of the modulus τ takes some special value, a residual subgroup of Γ N would be preserved. We derive the fixed points τ S = i, τ ST = (−1 + i √ 3)/2, τ T S = (1 + i √ 3)/2, τ T = i∞ in the fundamental domain which are invariant under the modular transformations indicated. We then generalise these fixed points to τ f = γτ S , γτ ST , γτ T S and γτ T in the upper half complex plane, and show that it is sufficient to consider γ ∈ Γ N . Focussing on level N = 4, corresponding to the flavour group S 4 , we consider all the resulting triplet modular forms at these fixed points up to weight 6. We then apply the results to lepton mixing, with different residual subgroups in the charged lepton sector and each of the right-handed neutrinos sectors. In the minimal case of two right-handed neutrinos, we find three phenomenologically viable cases in which the light neutrino mass matrix only depends on three free parameters, and the lepton mixing takes the trimaximal TM1 pattern for two examples. One of these cases corresponds to a new Littlest Modular Seesaw based on CSD(n) with n = 1 + √ 6 ≈ 3.45, intermediate between CSD (3) and CSD(4). Finally, we generalize the results to examples with three right-handed neutrinos, also considering the level N = 3 case, corresponding to A 4 flavour symmetry. *

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“…The so-called TM1 mixing matrix indicates the following sum rule among the Dirac CP phase δ CP and mixing angles cos δ CP = (3 − 5 cos 2θ 13 ) cot 2θ 23 4 sin θ 13 √ 3 cos 2θ 13 − 1 .…”

Section: Mixing Patterns Derived From S 4 With No Neutrino Massesmentioning

confidence: 99%

“…The neutrino masses m 2 2 and m 2 3 are dependent on free parameters m a and r. If we require that all the three lepton mixing angles and two mass squared differences lie in their corresponding experimentally 3σ intervals [1]. Then the lepton mixing parameters and the neutrino masses are predicted to be 0.3362 ≤ sin 2 θ 12 ≤ 0.3364, 0.02254 ≤ sin 2 θ 13 ≤ 0.02280, 0.556 ≤ sin 2 θ 23 We see that all mixing parameters and neutrino masses are restricted in rather narrow regions. It is straightforward to show that the model above is a powerful model to predicted lepton mixing parameters and neutrino masses, especially for mixing angle θ 12 .…”

Section: The Structure Of the Modelmentioning

confidence: 99%

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Lepton mixing predictions from S4 in the tridirect CP approach to two right-handed neutrino models

Ding

King

2019

Phys. Rev. D

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We perform an exhaustive analysis of all possible breaking patterns arising from S 4 H CP in a new tri-direct CP approach to the minimal seesaw model with two right-handed neutrinos, and construct a realistic flavour model along these lines. According to this approach, separate residual flavour and CP symmetries persist in the charged lepton, "atmospheric" and "solar" right-handed neutrino sectors, i.e. we have three symmetry sectors rather than the usual two of the semi-direct CP approach (charged leptons and neutrinos). Following the tri-direct CP approach, we find twenty-six kinds of independent phenomenologically interesting mixing patterns. Eight of them predict a normal ordering (NO) neutrino mass spectrum and the other eighteen predict an inverted ordering (IO) neutrino mass spectrum. For each phenomenologically interesting mixing pattern, the corresponding predictions for the PMNS matrix, the lepton mixing parameters, the neutrino masses and the effective mass in neutrinoless double beta decay are given in a model independent way. One breaking pattern with NO spectrum and two breaking patterns with IO spectrum corresponds to form dominance. We find that the lepton mixing matrices of three kinds of breaking patterns with NO spectrum and one form dominance breaking pattern with IO spectrum preserve the first column of the tri-bimaximal (TB) mixing matrix, i.e. yield a TM1 mixing matrix. *

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Fitting high-energy Littlest Seesaw parameters using low-energy neutrino data and leptogenesis

Cited by 25 publications

References 68 publications

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

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

Modular S4 and A4 symmetries and their fixed points: new predictive examples of lepton mixing

Lepton mixing predictions from S4 in the tridirect CP approach to two right-handed neutrino models

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