Related papers: A Modular $SU(5)$ Littlest Seesaw
In this note, a ``littlest higgs'' model is presented which has an approximate custodial SU(2) symmetry. The model is based on the coset space $SO(9)/(SO(5)\times SO(4))$. The light pseudo-goldstone bosons of the theory include a {\it…
We propose a model for leptons based on the smallest modular finite group $\Gamma_2\cong S_3$ that, for the first time, accounts for both the hints of large low-energy CP-violation in the lepton sector and the matter-antimatter asymmetry of…
We consider the problem of neutrino masses and mixing within the general framework of standard (type-I) seesaw models leading to three light neutrinos. Under the assumption of a hierarchical neutrino mass spectrum \lambda^4: \lambda : 1,…
In a recent paper, we showed that tree level up-down unification of fermion Yukawa couplings is a natural consequence of a large class of supersymmetric models. They can lead to viable quark masses and mixings for moderately large values of…
We derive predictions for Yukawa coupling ratios within GUTs generated from operators with mass dimension four and five. These relations are a characteristic property of unified flavour models and can reduce the large number of free…
We construct a gauge $B-L$ model with $D_4\times Z_4\times Z_2$ symmetry that can explain the quark and lepton mass hierarchies and their mixings with the realistic CP phases via the type-I seesaw mechanism. Six quark mases, three quark…
We review recent developments in theoretical models for neutrino masses and mixing. Emphases are given to models based on finite group family symmetries. In particular, we describe one recent model based on SU(5), in which both the…
A left-right model of quarks and leptons based on the gauge group $SU(3)_c \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$ is studied. Here the scalar sector consists of only two doublets namely (1,2,1,1) and (1,1,2,1) but familiar…
We consider the possibility of grand unification of the $\mathrm{ SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model in an SU(6) gauge unification group. Two possibilities arise. Unlike other conventional grand unified theories, in SU(6) one…
We consider a supersymmetric type-I seesaw framework with non-universal scalar masses at the GUT scale to explain the long-standing discrepancy of the anomalous magnetic moment of the muon. We find that it is difficult to accommodate the…
We present a minimal model of asymptotic grand unification based on an $SU(5)$ gauge theory in a compact $S^1/(\mathbb{Z}_2 \times \mathbb{Z}'_2)$ orbifold. The gauge couplings run to a unified fixed point in the UV, without supersymmetry.…
We study a successful model to explain the muon anomalous magnetic moment originating from Yukawa-type interactions {in a supersymmetric theory}. Thanks to a modular $A_4$ flavor symmetry, any lepton flavor violations that spoil the model…
We study models of supersymmetric grand unification based on the SO(10) gauge group. We investigate scenarios of non-universal gaugino masses including models containing a mixture of two representations of hidden sector chiral superfields.…
That $\mu \to e, \gamma$ and $\tau \to \mu,\gamma$ are sensitive probes of SUSY models with a see-saw mechanism is a well accepted fact. Here we propose a `top-down' approach in a general SUSY SO(10) scheme. In this framework, we show that…
A realistic extension of the minimal $SU(5)$ theory consisting of the addition of an adjoint fermion is known to predict light real fermion and scalar weak triplets, potentially accessible at the LHC. These particles, in addition to playing…
Fermion masses and mixing angles are studied in an SUSY $SO(10)\times \Delta (48)\times U(1)$ model with small $\tan\beta$. Thirteen parameters involving masses and mixing angles in the quark and charged lepton sector are successfully…
Gauge-Higgs grand unification theories are models of gauge-Higgs unification that extend the electroweak group into a simple group that includes the color symmetry. The minimal option is a gauge-Higgs grand unification based on the SU(6)…
Gauge-Yukawa Unification (GYU) is obtained in GUTs by searching for renormalization group invariant relations among gauge and Yukawa couplings beyond the unification scale. Of particular interest are two supersymmetric GUTs, the finite and…
We study a model of neutrino and dark matter within the framework of a minimal extended seesaw. This framework is based on $A_4$ flavor symmetry along with the discrete $Z_4$ symmetry to stabilize the dark matter and construct desired mass…
We explore in detail the effective matter fermion mass sum-rules in a class of renormalizable SUSY SO(10) grand unified models where the quark and lepton mass and mixing patterns originate from non-decoupling effects of an extra vector…