We propose a model based on modular A4 symmetry containing a dark matter candidate, realizing radiatively induced neutrino mass at one-loop level. One finds that stability of dark matter candidate ...can be assured by nonzero value of modular weight and heavy neutral fermion mass hierarchies, which include dark matter under the A4 triplet, are uniquely determined; MX≪M2<M3. Therefore we clearly identify single dark matter field which can discriminate from the other models with A4 modular symmetry. Then we discuss several phenomenological aspects and show predictions on the lepton sector. Especially, we find 0.56≲sin2θ23≲0.624, which could have an advantage of this narrow region and be also discriminated from the other modular A4 models.
Abstract We discuss the modular A 4 invariant model of leptons combining with the generalized CP symmetry. In our model, both CP and modular symmetries are broken spontaneously by the vacuum ...expectation value of the modulus τ. The source of the CP violation is a non-trivial value of Reτ while other parameters of the model are real. The allowed region of τ is in very narrow one close to the fixed point τ = i for both normal hierarchy (NH) and inverted ones (IH) of neutrino masses. The CP violating Dirac phase δ CP is predicted clearly in 98°, 110° and 250°, 262° for NH at 3 σ confidence level. On the other hand, δ CP is in 95°, 100° and 260°, 265° for IH at 5 σ confidence level. The predicted ∑m i is in 82, 102 meV for NH and ∑m i = 134, 180 meV for IH. The effective mass 〈m ee 〉 for the 0νββ decay is predicted in 12.5, 20.5 meV and 54, 67 meV for NH and IH, respectively.
We propose a radiative seesaw model based on a modular A4 symmetry, which has good predictability in the lepton sector. We execute a numerical analysis to search for parameters that satisfy the ...experimental constraints such as those from neutrino oscillation data and lepton flavor violations. Then, we present several predictions in our model that originate from the modular symmetry at a fixed point as well as fundamental region of τ.
We propose a minimal extension of the Standard Model where neutrino masses are generated radiatively at one-loop level via Scotogenic scenario. The model is augmented with A4 modular symmetry as a ...scotogenic and flavor symmetry. With minimal number of parameters, the model makes predictions for neutrino oscillation data, Majorana and Dirac phases, dark matter characteristics, and neutrinoless double beta decay.
We discuss an inverse seesaw model based on right-handed fermion specific U(1) gauge symmetry and A4-modular symmetry. These symmetries forbid unnecessary terms and restrict structures of Yukawa ...interactions which are relevant to inverse seesaw mechanism. Then we can obtain some predictions in neutrino sector such as Dirac-CP phase and sum of neutrino mass, which are shown by our numerical analysis. Besides the relation among masses of heavy pseudo-Dirac neutrino can be obtained since it is also restricted by the modular symmetry. We also discuss implications to lepton flavor violation and collider physics in our model.
In this study, we investigate muon g−2, RK(⁎), and RD(⁎) anomalies in a specific model with one doublet, one triplet, and one singlet scalar leptoquark (LQ). When the strict limits from the ℓ′→ℓγ, ...ΔB=2, Bs→μ+μ−, and B+→K+νν¯ processes are considered, it is difficult to use one scalar LQ to explain all of the anomalies due to the strong correlations among the constraints and observables. After ignoring the constraints and small couplings, the muon g−2 can be explained by the doublet LQ alone due to the mt enhancement, whereas the measured and unexpected smaller RK(⁎) requires the combined effects of the doublet and triplet LQs, and the RD and RD⁎ excesses depend on the singlet LQ through scalar- and tensor-type interactions.
We propose a gauged U(1)B−L extended two Higgs doublet model to explain both neutrino mass and lepton anomalous magnetic moments (g−2). Neutrino mass is generated via an inverse seesaw mechanism by ...introducing singlet fermions. Especially, we update the result of muon (g−2) in light of the very recent report by E989 experiment at Fermilab, indicating aμFNAL=116592040(54)×10−11. Combining BNL result, we have the following deviation from the standard model prediction Δaμ=(2.51±5.9)×10−10 at 4.2 σ. Thanks to an appropriate assignment for U(1)B−L×Z2 symmetry and larger (20≲)tanβ that is favored by type-X model, we realize natural hierarchies among neutral fermions. The lepton anomalous magnetic moments can be induced at the one loop level by introducing an iso-spin singlet singly-charged boson. This charged scalar plays a significant role in evading chiral suppression of these phenomenologies. We show sizable lepton (g−2) can be obtained after satisfying all the flavor constraints, such as μ→eγ and flavor conserving leptonic Z boson decays.
A
bstract
We study a symmetry breaking of residual flavor symmetries realized at fixed points of the moduli space. In the supersymmetric modular invariant theories, a small departure of the modulus ...from fixed points is required to realize fermion mass hierarchies and sizable CP-breaking effects. We investigate whether one can dynamically fix the moduli values in the vicinity of the fixed points in the context of Type IIB string theory. It is found that the string landscape prefers |
δτ
| ≃ 10
−
5
for the deviation of the complex structure modulus from all fixed points and the CP-breaking vacuum is statistically favored. To illustrate phenomenological implications of distributions of moduli values around fixed points, we analyze the lepton sector on a concrete
A
4
modular flavor model.
We discuss radiative neutrino mass models with a general lepton flavor dependent U(1) gauge symmetry. The scotogenic model is adopted for neutrino mass generation in which Z2 odd singlet fermions and ...an inert scalar doublet are introduced. A lepton flavor dependent local U(1) symmetry is applied to realize two-zero texture of a Majorana mass matrix of Z2 odd singlet fermions where we explore minimal construction choosing U(1) charges of the standard model fermions and singlet fermions. Then we investigate neutrino mass matrix and show some predictions for constructed models, and discuss some phenomenological implications.
(N‐Phenylfluorenylidene)acridane (Ph‐FA) compounds with electron‐withdrawing and ‐donating substituents (H, MeO, Ph, NO2, Br, F) at the para position of the phenyl group were successfully synthesized ...by Barton–Kellogg reactions of N‐aryl thioacridones and diazofluorene. By using the substituent on the nitrogen atom to alter the electronic properties, both the folded and twisted conformers of p‐NO2‐C6H4‐FA could be crystallographically characterized, which enabled the charge transfer from the electron‐donating acridane moiety to the electron‐accepting fluorenylidene moiety to be understood. Ground‐state mechanochromism, thermochromism, vapochromism, and proton‐induced chromism were demonstrated between the folded and twisted conformations of the conformers. Protonation and chemical oxidation of Ph‐FA gave two stable acridinium compounds, namely, the fluorenylacridinium and acridinium radical cations. The present study will contribute to the development of functional dyes and organic semiconductors.
Color control: (N‐Phenylfluorenylidene)acridane compounds with electron‐withdrawing and ‐donating substituents at the para position of the phenyl group were synthesized and the X‐ray crystal structures of both the folded and twisted conformers of the nitro derivative determined. Not only do the compounds show various chromic properties, carrier transport properties are also evident.
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