arXiv subjects

Mitesh Kumar Behera

Publications and source records attributed to Mitesh Kumar Behera.

17 recordsLinked to original sources

arXiv2026

Probing Non-Holomorphic Modular $A_4$ Double Seesaw: Signatures in Neutrino Oscillation Experiments and Implications for Leptogenesis

We realize the double seesaw mechanism within a non-holomorphic modular $A_4$ framework by extending the Standard Model with three generations of right-handed neutrinos (RHNs), three left-handed sterile neutrino fields, and an $A_4$-singlet scalar. The modular construction forbids a bare Majorana mass term for the RHNs and realizes the hierarchy required for the double seesaw, with RHN masses induced through the heavier sterile neutrino sector. A comprehensive scan of the modular parameter space yields viable normal ordering solutions consistent with current neutrino oscillation data. We further examine their testability at DUNE, T2HK, and JUNO. DUNE and T2HK strongly probe the atmospheric mixing parameters and constrain the allowed model space, while JUNO provides complementary precision sensitivity to the solar mixing angle and mass-squared splitting. The oscillation compatible points also determine the induced RHN spectrum and complex Yukawa textures relevant for thermal leptogenesis. For a representative unflavored benchmark in the strong-washout regime, numerical Boltzmann evolution including decays and inverse decays yields $Y_{\Delta B}\simeq8.11\times10^{-11}$, close to the observed baryon asymmetry. The allowed parameter space also admits an $N_1$-dominated two-flavor thermal leptogenesis realization with a hierarchical, non-resonant RHN spectrum. Our results establish the non-holomorphic modular $A_4$ double seesaw as a predictive framework linking low-energy neutrino phenomenology and thermal leptogenesis, with oscillation predictions directly testable at forthcoming precision neutrino experiments.

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arXiv2026

A Non-Holomorphic Modular $A_4$ Framework for Resonant Leptogenesis with Gravitational Wave Signatures

We study a type-I seesaw framework based on non-holomorphic $A_4$ modular symmetry, where polyharmonic Maa\ss\ forms construct the Yukawa couplings and right-handed neutrino (RHN) Majorana mass matrix. The use of non-holomorphic modular forms yields highly constrained neutral lepton mass matrices with a more restrictive lepton-sector structure and naturally generates a quasi-degenerate RHN mass spectrum, enabling resonant leptogenesis at an intermediate scale with RHN masses of $\mathcal{O}(10^3)$ TeV without requiring an ad hoc mass degeneracy. We further extend the model by introducing a complex scalar field $(\Phi)$ charged under $\mathbb{Z}_3$ symmetry. The spontaneous breaking of the discrete symmetry after the phase transition associated with $\Phi$ leads to domain-wall (DW) formation. A radiatively induced bias term associated with the RHN sector triggers DW annihilation, resolving the cosmological DW problem, and producing a stochastic gravitational wave (GW) signal that indirectly probes the RHN mass scale. The accompanying first-order phase transition produces a second GW peak, yielding a characteristic double-peaked spectrum with frequencies separated by several orders of magnitude and potentially observable by complementary future GW detectors.

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arXiv2026

A Predictive Non-Holomorphic Modular $A_4$ Linear Seesaw Framework Testable at DUNE

We study a realization of neutrino masses and mixing phenomena within a linear seesaw mechanism based on non-holomorphic modular $A_4$ symmetry, which extends modular-invariant flavor models beyond the conventional holomorphic framework. The model is constructed in a non-supersymmetric setting and involves six heavy $SU(2)_L$ singlet fermions, $N_{Ri}$ and $S_{Li}$, together with a single flavon field, thereby significantly reducing the field content compared to conventional $A_4$ flavor models that typically require multiple flavon fields as well as supersymmetric (holomorphic) modular frameworks involving additional superfields. The modular transformation properties of the Yukawa couplings under $A_4$ symmetry lead to a highly constrained neutrino mass matrix with a distinctive flavor structure. After presenting the general theoretical framework, we perform a systematic numerical analysis of neutrino phenomenology by restricting the modulus parameter $\tau$ to the fundamental domain and scanning the allowed parameter space. We identify regions consistent with current neutrino oscillation data at the $3\sigma$ level and obtain predictions for currently unknown observables, including the absolute neutrino mass scale and leptonic CP-violating phases. We further examine the implications for neutrinoless double beta decay, highlighting testable signatures in the upcoming precision oscillation as well as rare-process experiments. These results demonstrate the phenomenological viability and predictive power of non-holomorphic modular symmetry in linear seesaw neutrino mass models.

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arXiv2025

Phenomenology of Inverse Seesaw Using $S_3$ Modular Symmetry

Describing neutrino masses using the inverse seesaw mechanism with discrete flavor symmetry imposed through modular forms provides a testable framework at TeV scales with fewer parameters. However, $S_3$, the smallest modular group, remains relatively underexplored. In this work, we construct the minimal supersymmetric inverse seesaw model based on the modular $S_3$ flavor symmetry. In our model, the light neutrino mass matrix depends on 6 real parameters: the complex modulus, an overall scale for light neutrino mass, a real ratio and a complex ratio of Yukawa coupling. Thanks to its minimality, our model offers various definite predictions: the lightest neutrino is massless, the neutrino masses are inverted ordering, the sum of the three light neutrino masses ($\sum_i m_i$) is 100 meV, the effective mass for the end point of the beta decay spectrum is 50 meV, the effective mass for neutrinoless double beta decay ($m_{ee}$) is in the range $38-58$ meV. In particular, the predicted values for $\sum_i m_i$ and $m_{ee}$ from our model are within reach of the next generation experiments. Our model also predicts radiative lepton flavor violating decays $\ell\to\ell'γ$ which are compatible with experimental constraints.

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arXiv2024

Exploring neutrino masses, $(g-2)_{μ, e}$ in type I+II seesaw in ${L^{}_e-L^{}_α}$ gauge extended model

This paper aims to explore the implications of $U(1)_{L_e-L_α}$ gauge symmetries, where $α=τ, μ$, in the neutrino sector through the type-(I+II) seesaw mechanisms. To achieve such a hybrid framework, we include a scalar triplet and three right-handed neutrinos. The model can successfully account for the active neutrino masses, mixing angles, mass squared differences, and the CP-violating phase within the $3 σ$ bounds of NuFit v5.2 neutrino oscillation data. The presence of new gauge boson at the MeV scale provides an explanation for the muon and electron $(g-2)$ within the confines of their experimental limits. Furthermore, we scrutinize the proposed models in the context of upcoming long-baseline neutrino experiments such as DUNE, P2SO, T2HK, and T2HKK. The findings reveal that P2SO and T2HK have the ability to probe both the models in their $5 σ$ allowed oscillation parameter region, whereas DUNE and T2HKK can conclusively test only model with $U(1)_{L_e-L_μ}$- symmetry within their $5 σ$ parameter space if the true values of the oscillation parameters remain consistent with NuFit v5.2.

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arXiv2024

Predictions from scoto-seesaw with $A_4$ modular symmetry

This paper's novelty lies in introducing a hybrid scoto-seesaw model rooted in $A_4$ discrete modular symmetry leading to several interesting phenomenological implications. The scoto-seesaw framework leads to generation of one mass square difference $( Δm^2_{\rm atm}$) using the type-I seesaw mechanism at the tree level. Additionally, the scotogenic contribution is vital in obtaining the other mass square difference ($Δm^2 _{\rm sol}$) at the loop level, thus providing a clear interpretation of the two different mass square differences. The non-trivial transformation of Yukawa couplings under the $A_4$ modular symmetry helps to explore neutrino phenomenology with a specific flavor structure of the mass matrix. In addition to predictions for neutrino mass ordering, mixing angles and CP phases, this setup leads to precise predictions for $\sum m_i$ as well as $|m_{ee}|$. In particular, the model predicts $\sum m_i \in (0.073,0.097)$ eV and $\left| m_{ee}\right| \in (3.15,6.66)\times 10^{-3} $ eV range; within reach of upcoming experiments. Furthermore, our model is also promising for addressing lepton flavor violations, i.e., $\ell_α\to \ell_βγ$, $\ell_α\to 3\ell_β$ and $μ- e $ conversion rates while staying within the realm of current experimental limits.

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arXiv2024

Neutrino phenomenology in the modular $S_3$ seesaw model

We have studied neutrino phenomenology in the supersymmetric type-I seesaw model endowed with the $Γ_2 \simeq S_3$ modular symmetry. We have identified different realizations of the $S_3$ modular symmetry, referred to as models A, B, C, and D. The 4 models are compatible with neutrino mass being inverted ordering (IO). Moreover, models A, B, and D can also accommodate normal ordering (NO) neutrino masses. We identify parameter space for each model compatible with neutrino oscillation at the 2-$σ$ level. We then proceed to study the neutrino phenomenology of each model. We find that the lightest neutrino mass can be as light as 0.64 meV in the case of NO in model A and 50 meV in the case of IO in model D. The smallest effective electron neutrino mass attainable in our analysis is 8.8 meV in the case of NO (model A), and 50 meV for IO (model D). Finally, we note that the effective Majorana mass can be as small as 0.33 meV in the case of NO (model A) and 22 meV for IO (model D).

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arXiv2023

Exploring Models with Modular Symmetry in Neutrino Oscillation Experiments

Our study aims to investigate the viability of neutrino mass models that arise from discrete non-Abelian modular symmetry groups, i.e., $Γ_N$ with ($N=1,2,3,\dots$) in the future neutrino experiments T2HK, DUNE, and JUNO. Modular symmetry reduces the usage of flavon fields compared to the conventional discrete flavor symmetry models. Theories based on modular symmetries predict the values of leptonic mixing parameters, and therefore, these models can be tested in future neutrino experiments. In this study, we consider three models based on the $A_4$ modular symmetry, i.e., Model-A, B, and C such a way that they predict different values of the oscillation parameters but still allowed with respect to the current data. In the future, it is expected that T2HK, DUNE, and JUNO will measure the neutrino oscillation parameters very precisely, and therefore, some of these models can be excluded in the future by these experiments. We have estimated the prediction of these models numerically and then used them as input to scrutinize these models in the neutrino experiments. Assuming the future best-fit values of $θ_{23}$ and $δ_{\rm CP}$ remain the same as the current one, our results show that at $5 σ$ C.L, Model-A can be excluded by T2HK whereas Model-B can be excluded by both T2HK and DUNE. Model-C cannot be excluded by T2HK and DUNE at $5 σ$ C.L. Further; our results show that JUNO alone can exclude Model-B at an extremely high confidence level if the future best-fit of $θ_{12}$ remains at the current-one. We have also identified the region in the $θ_{23}$ - $δ_{\rm CP}$ parameter space, for which Model-A cannot be separated from Model-B in T2HK and DUNE.

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arXiv2023

Unveiling neutrino phenomenology, $(g-2)_{e,μ}$ and leptogenesis through U(1) gauge symmetries in an inverse seesaw model

The proposed work is an extension of the Standard Model, where we have introduced two gauge symmetries, i.e., $U(1)_{B-L}$ and $U(1)_{L_e-L_μ}$ to study neutrino phenomenology, muon, and electron $(g-2)$ as well as leptogenesis using the inverse seesaw mechanism. For this purpose, we have included three right-handed neutrinos $N_{R_i}$, three neutral fermions $S_{L_i} (i =1,2,3)$ and two scalar singlet bosons ($χ_1$ and $χ_2$). We get a definite structure for the neutrino mass matrix due to the aforementioned gauge symmetries. Thus, our model is able to predict the neutrino oscillation results, which are in accordance with the experimental data and is inclined towards normal ordering. The outcomes comprise the active neutrino masses, mixing angles, mass squared differences, CP-violating phase, etc. Moreover, since the extended gauge symmetries are local, there are corresponding gauge bosons, denoted as $Z_{B-L}$ and $Z_{e μ}$. Of these, mass of $Z_{B-L}$ is $\mathcal{O}$(TeV) range to satisfy the collider constraint, while the mass of $Z_{e μ}$ is in the MeV range, making it feasible to account for current electron and muon $(g-2)$ results via neutral current interactions. Furthermore, our model is able to account for leptogenesis, which can demonstrate the matter-antimatter asymmetry of the universe. Additionally, we have carried out the prospect of probing our model in the context of upcoming long baseline experiments: DUNE, T2HK, and T2HKK, at a confidence level of $5σ$. From the result it is clear that, our model can be tested in its $3σ$ C.L. with $5σ$ allowed region of DUNE, T2HK and T2HKK.

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arXiv2023

Neutrino phenomenology, W mass anomaly & muon $(g-2)$ in minimal type-III seesaw using $T^\prime$ modular symmetry

In this study, we attempt to introduce a model to illustrate neutrino phenomenology by incorporating two right-handed fermion triplet superfields, i.e., $Σ_{R_j}$, in the presence of the modular symmetry $Γ_3^\prime \simeq A_4^\prime$, a double cover of the $A_4$ modular symmetry. The motivation in utilizing double cover is, so far only even modular forms were considered for constructing modular invariant models, but, in this case, it is possible to extend the modular invariance approach to general integral weight modular forms, i.e., the odd weight modular forms. Hence, this type of amalgamation between $T^\prime$ modular symmetry and minimally extending the seesaw can correctly explain the neutrino phenomenology. Additionally, we have made an attempt to accommodate the most recent measurement of the $W$ boson mass, published by the CDF-II collaboration and shed some light on the recent results of muon $(g-2)$. Finally, we have discussed lepton flavor violation in order to establish a constraint on the mass of right-handed fermion.

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arXiv2023

Neutrino Phenomenology from Democratic Approach

In this article, we derive the tiny neutrino masses and mixings from the democratic and diagonal texture approach, which consistent with the recent experimental oscillation data. The unitary rotation matrices, which diagonalize the neutrino mass matrices are obtained by a specific parametrization of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. From which, we tried to calculate all three mixing angles as well as the Dirac CP-violating phase interms of model mixing parameters. In particular, the deviation from the tribimaximal mixing is explained in this model. Along with the Jarlskog parameter in terms of model parameter and neutrino-less double beta decay (NDBD) has been discussed briefly.

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arXiv2022

Type III seesaw under $A_4$ modular symmetry with leptogenesis

We make an attempt to study neutrino phenomenology in the framework of type-III seesaw by considering $A_4$ modular symmetry in the super-symmetric context. In addition, we have included a local $U(1)_{B-L}$ symmetry which eventually helps us to avoid certain unwanted terms in the superpotential. Hitherto, the seesaw being type-III, it involves three fermion triplet superfields $Σ_R$, along with which, we have included a singlet weighton field $(ρ)$. In here, modular symmetry plays a crucial role by avoiding the usage of excess flavon (weighton) fields. Also, the Yukawa couplings acquire modular forms which are expressed in terms of Dedekind eta function $η(τ)$. However, for numerical analysis we use $q$ expansion expressions of these couplings. Therefore, the model discussed here is triumphant enough to accommodate the observed neutrino oscillation data and also successfully explains observed baryon asymmetry of the universe through leptogenesis.

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arXiv2022

Implications of $A_4$ modular symmetry on Neutrino mass, Mixing and Leptogenesis with Linear Seesaw

The present work is inspired by the application of $A_4$ modular symmetry in the linear seesaw framework, which restricts the use of multiple flavon fields. Linear seesaw is realized with six heavy $SU(2)_L$ singlet fermion superfields and a weighton in a supersymmetric framework. The non-trivial transformation of Yukawa couplings under the $A_4$ modular symmetry helps to explore the neutrino phenomenology with a specific flavor structure of the mass matrix. We discuss the phenomena of neutrino mixing and show that the obtained mixing angles and CP violating phase in this framework are compatible with the observed $3σ$ range of the current oscillation data. In addition, we also investigate the non-zero CP asymmetry from the decay of lightest heavy fermion superfield to explain the preferred phenomena of baryogenesis through leptogenesis including flavor effects.

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arXiv2022

Linear seesaw in $A^\prime_5$ modular symmetry with Leptogenesis

In this paper, we investigate the implication of modular $Γ^{\prime}_5 \simeq A^{\prime}_5$ symmetry on neutrino oscillation phenomenology in the linear seesaw framework. In order to achieve the well defined mass structure for the light active neutrinos as dictated by the linear seesaw mechanism, we introduce six heavy fermion fields along with a pair of weightons to retain the holomorphic nature of the superpotential. The notable feature of modular symmetry is that, it reduces the usage of flavon fields significantly. In addition, the Yukawa couplings transform non-trivially under the flavor symmetry group and expressed in terms of the Dedekind eta functions, the $q$ expansion of which renders numerical simplicity in calculations. We demonstrate that the model framework diligently accommodates all the neutrino oscillation data. Alongside, we also investigate the effect of CP asymmetry generated from the decay of lightest heavy fermions to explain the observed baryon asymmetry through the phenomenon of leptogenesis.

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arXiv2021

Inverse seesaw in $A_5^\prime$ modular symmetry

We make an investigation of modular $Γ^{\prime}_5 \simeq A^{\prime}_5$ group in inverse seesaw framework. Modular symmetry is advantageous because it reduces the usage of extra scalar fields significantly. Moreover, the Yukawa couplings are expressed in terms of Dedekind eta functions, which also have a $q$ expansion form, utilized to achieve numerical simplicity. Our proposed model includes six heavy fermion superfields i.e., $\mathcal{N}_{Ri}$, $\mathcal{S}_{Li}$ and a weighton. The study of neutrino phenomenology becomes simplified and effective by the usage of $A^\prime_5$ modular symmetry, which provides us a well defined mass structure for the lepton sector. Here, we observe that all the neutrino oscillation parameters, as well as the effective electron neutrino mass in neutrinoless double beta decay can be accommodated in this model. We also briefly discuss the lepton flavor violating decays $\ell_i \to \ell_j γ$ and comment on non-unitarity of lepton mixing matrix.

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arXiv2020

A modular $A_4$ symmetric Scotogenic model for Neutrino mass and Dark Matter

Modular symmetries have been impeccable in neutrino and quark sectors. This motivated us, therefore, to propose a variant of scotogenic model based on modular $A_4$ symmetry to realize the neutrino mass generation at one-loop level through radiative mechanism. Alongside, the lepton flavour violating process $μ\to e γ$ and the muon $g-2$ anomaly are also addressed. The lightest Majorana fermions turn out to be potential dark matter candidates, made stable by suitable assignment of modular weights. The relic density of the same has been computed with annihilations mediated by inert scalars and new $U(1)$ gauge boson.

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arXiv2020

Neutrino Phenomenology and Dark matter in an $A_4$ flavour extended B-L model

We present an $A_4$ flavor extended $\rm B-L$ model for realization of eV scale sterile neutrinos, motivated by the recent experimental hints from both particle physics and cosmology. The framework considered here is a gauged $\rm B-L$ extension of standard model without the introduction of right-handed neutrinos, where the gauge triangle anomalies are canceled with the inclusion of three exotic neutral fermions $N_{i}$ ($i=1,2,3$) with $\rm B-L$ charges $-4,-4$ and $5$. The usual Dirac Yukawa couplings between the SM neutrinos and the exotic fermions are absent and thus, the model allows natural realization of eV scale sterile-like neutrino and its mixing with standard model neutrinos by invoking $\rm A_4$ flavor symmetry. We demonstrate how the exact tri-bimaximal mixing pattern is perturbed due to active-sterile mixing by analyzing $1+3$ case in detail. We also show the implication of eV scale sterile-like neutrino on various observables in neutrino oscillation experiments and the effective mass in neutrinoless double beta decay. Another interesting feature of the model is that one of three exotic fermions is required to explain eV scale phenomena, while other two fermions form stable dark matter candidates and their total relic density satisfy the observed $3σ$ limit of Planck data. We constrain the gauge parameters associated with $U(1)$ gauge extension, using relic density and collider bounds.

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