Repressing anarchy in neutrino mass textures

Self Cite

We update a five-dimensional SO(10) grand unified model of fermion masses and mixing angles originally proposed by Kitano and Li. In our setup Yukawa couplings are anarchical and quark and lepton sectors are diversified by the profiles of the fermion zero modes in the extra dimension. The breaking of SO(10) down to SU(5)×U(1) X provides the key parameter that distinguishes the profiles of the different SU(5) components inside the same 16 representation. With respect to the original version of the model, we extend the Higgs sector to explicitly solve the doublet-triplet splitting problem through the missing partner mechanism and we perform a fit to an idealized set of data. By scanning the Yukawa couplings of the model we find that, for large tan β, both normal and inverted ordered neutrino spectrum can be accommodated. However, while the case of inverted order requires a severe fine tuning of the Yukawa parameters, the normal ordering is compatible with an anarchical distribution of Yukawa couplings. Thus, in a natural portion of the parameter space, the model predicts a normal ordered neutrino spectrum, the lightest neutrino mass below 5 meV, and |m ββ | in the range 0.1-5 meV. No particular preference is found for the Dirac CP phase in the lepton sector while the right-handed neutrino masses are too small to explain the baryon asymmetry of the universe through thermal leptogenesis.

Section: Jhep09(2014)095mentioning

confidence: 52%

Order and anarchy hand in hand in 5D SO(10)

Feruglio

Patel

Vicino

2014

Self Cite

“…In addition each entry acquires a random phase from 0 to 2π, and M N is symmetrised. Following [55] we take λ ≈ 0. Having chosen viable neutrino models we calculate the widths of the right handed neutrino states (see appendix A) and estimate ∆N eff following the numerical procedure described in appendix B.…”

Section: Jhep07(2017)023mentioning

confidence: 99%

Cosmology in Mirror Twin Higgs and neutrino masses

Chacko

Craig

Fox

et al. 2017

112

169

We explore a simple solution to the cosmological challenges of the original Mirror Twin Higgs (MTH) model that leads to interesting implications for experiment. We consider theories in which both the standard model and mirror neutrinos acquire masses through the familiar seesaw mechanism, but with a low right-handed neutrino mass scale of order a few GeV. In these νMTH models, the right-handed neutrinos leave the thermal bath while still relativistic. As the universe expands, these particles eventually become nonrelativistic, and come to dominate the energy density of the universe before decaying. Decays to standard model states are preferred, with the result that the visible sector is left at a higher temperature than the twin sector. Consequently the contribution of the twin sector to the radiation density in the early universe is suppressed, allowing the current bounds on this scenario to be satisfied. However, the energy density in twin radiation remains large enough to be discovered in future cosmic microwave background experiments. In addition, the twin neutrinos are significantly heavier than their standard model counterparts, resulting in a sizable contribution to the overall mass density in neutrinos that can be detected in upcoming experiments designed to probe the large scale structure of the universe.

“…An estimation of the range of value it may acquire takes into consideration that ǫ should remain in the perturbative regime and that the value of v Φ is expected to be not so much smaller than Λ Φ (without a dynamical mechanism to explain it). In this letter, ǫ is taken in the interval [0.01, 0.3], consistently with previous studies on FN models [6,7]. The logarithm in eq.…”

Section: Jhep10(2017)168mentioning

confidence: 90%

“…Once the scalar field φ, typically called flavon, develops a vacuum expectation value (VEV) the flavour symmetry is spontaneously broken and the Yukawa matrices can be written in terms of powers of φ /Λ F . Fermion mass hierarchies and mixing angles can then be explained by an appropriate choice of the FN charges [2][3][4][5][6][7]. The large number of free parameters, one for each entry of the Yukawa matrices, has the drawback of lowering the predictive power of the model: any value of fermion masses and mixings can indeed be reproduced.…”

Section: Introductionmentioning

confidence: 99%

The minimal flavour violating axion

Arias-Aragón

Merlo

2017

The solution to the Strong CP problem is analysed within the Minimal Flavour Violation (MFV) context. An Abelian factor of the complete flavour symmetry of the fermionic kinetic terms may play the role of the Peccei-Quinn symmetry in traditional axion models. Its spontaneous breaking, due to the addition of a complex scalar field to the Standard Model scalar spectrum, generates the MFV axion, which may redefine away the QCD theta parameter. It differs from the traditional QCD axion for its couplings that are governed by the fermion charges under the axial Abelian symmetry. It is also distinct from the so-called Axiflavon, as the MFV axion does not describe flavour violation, while it does induce flavour non-universality effects. The MFV axion phenomenology is discussed considering astrophysical, collider and flavour data.