arXiv subjects

Mrinal Kumar Das

Publications and source records attributed to Mrinal Kumar Das.

At least 19 recordsLinked to original sources

arXiv2026

Gravitational Wave in an $A_4 \otimes Z_4$ Neutrino Model with Generalised CP

We extend the Standard Model with an $A_4 \times Z_4$ flavor symmetry and generalized CP (GCP) symmetry, realized through two flavon triplets that spontaneously break $A_4$ and generate the observed lepton mixing pattern. A new $A_4$-singlet flavon couples to one of these triplets through a complex quartic interaction that breaks GCP and fixes the reactor mixing angle; this same coupling biases the domain walls formed when that triplet breaks $A_4$. A global fit to oscillation data reproduces all mixing angles and mass splittings, predicting a maximal Dirac CP phase of $270^\circ$ and an effective Majorana mass near $15\text{ meV}$, testable by upcoming neutrinoless double-beta-decay ($0\nu\beta\beta$) experiments. The same coupling generates a stochastic gravitational-wave background peaking in the pulsar-timing-array and LISA bands, with peak frequency and amplitude predicted to scale as $\sin\theta_{13}$ and $\sin^{-4}\theta_{13}$, a falsifiable link between neutrino oscillation and gravitational-wave (GW) observations.

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arXiv2026

Neutrino Mass and its Impact on Gravitational Waves from Domain Wall Collision

The $A_{4} \times Z_{4}$ symmetry models are constructed to study neutrino masses and mixings, as well as the gravitational-wave spectrum from domain-wall annihilation. The first neutrino mass model is constructed with the flavon's vacuum expectation value and alignment obtained from the self-interacting potential terms, while the second model uses a new vacuum expectation value arising from a potential containing both self-interaction and mixed terms. The resulting neutrino mixing patterns for both models are in good agreement with current neutrino oscillation data with different mixing values. Further, the flavon mixing terms lift the vacua degeneracy that often shows in the spontaneous symmetry breaking of the discrete symmetry. These mixing terms and the modified neutrino mass matrix of the second model are considered to produce the necessary bias for analysing the gravitational waves spectrum. The spectrum predicted by the model could be detected by current and near-future experiments when the flavons have the vacuum expectation value of $10^4$ TeV.

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arXiv2025

Neutrino Textures from Modular $A_4$ Left--Right Symmetry: Experimental Signatures at DUNE and T2HK in the Post-JUNO Era

We have realized different two-zero textures within the framework of the left right symmetric model using the $\Gamma_{3}\cong A_{4}$ modular group. The matter multiplets of the model are assigned as three singlet representations of the $A_{4}$ group, and their charge assignments together with the modular weights of the Yukawa couplings are chosen in such a way that different two-zero textures of the neutrino mass matrix are obtained. In total, we have successfully realized seven different two-zero textures. Furthermore, we have studied neutrinoless double beta decay and lepton flavor violating (LFV) processes, and have calculated the effective Majorana mass and the branching ratios for LFV processes for each of the textures. We further probe these two-zero textures at the long-baseline neutrino experiments DUNE and T2HK. We find that DUNE, especially when combined with T2HK, can significantly restrict the $\theta_{23}-\delta_{\rm CP}$ parameter space predicted by these textures. Moreover, the inclusion of high-precision determinations of $\theta_{12}$ (from JUNO) and $\theta_{13}$ leads to a substantial, further reduction of the allowed parameter space. For assumed inverted mass ordering, the synergy of DUNE and T2HK leads to a highly predictive scenario for the $B_{2}$ and $B_{4}$ textures, as the allowed regions collapse into tiny islands near the CP-conserving points in the lower and higher octant of $\theta_{23}$, respectively.

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arXiv2025

Neutrino phenomenology and Dark matter in a left-right asymmetric model with non-holomorphic modular $A_{4}$ group

We present a model constructed within a non-supersymmetric framework capable of explaining both current neutrino oscillation data and the observed dark matter relic abundance. In this study, the Yukawa couplings are expressed as polyharmonic Maa\ss{} forms, and the non-supersymmetric left-right symmetric model is realized through the $\Gamma_{3}$ modular group, with neutrino masses generated via the Type II seesaw dominance mechanism. The analysis focuses on determining the neutrino oscillation parameters, the effective Majorana mass arising from the standard contribution, and the dark matter relic density. Our results indicate that the model strongly favours the normal mass hierarchy over the inverted one and prefers the lower octant for the mixing angle $\theta_{23}$. Furthermore, the effective Majorana mass is predicted to lie in the range $10^{-3}\,\text{eV}$ to $0.1\,\text{eV}$. In addition, the lightest sterile neutrino present in the model is considered a viable dark matter candidate. A sterile neutrino mass in the range $10~\text{keV}$ to $30~\text{keV}$ is found to yield consistent results for both the relic density and active-sterile mixing angles.

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arXiv2025

Froggatt-Nielsen like mechanism in the framework of Modular Symmetry for Neutrino Mass, Mixing and Leptogenesis

We study a neutrino mass model with Froggatt-Nielsen (FN) like modular symmetry. The FN mechanism requires an additional gauge symmetry, $U(1)_{FN}$, which is spontaneously broken at high energies. But in this work, we do not need an extra symmetry as modular weights play the role of the FN charges of the additional $U(1)_{FN}$ symmetry. We have constructed a neutrino mass model using FN-like modular symmetry in the $T'$ group. This model can accommodate neutrino oscillation parameters and also address other phenomena beyond the Standard Model, such as neutrinoless double beta decay and the baryon asymmetry of the universe.

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arXiv2025

Matter-antimatter asymmetry in minimal inverse seesaw framework with $A_4$ modular symmetry

We propose a minimal inverse seesaw framework based on $A_4$ modular symmetry. We have studied the neutrino oscillation parameters in our work and our model excludes some $3 \sigma$ values of the mixing angle $\theta_{23}$. Also, there is a clear linear relation between the mixing angles $\theta_{12}$ and $\theta_{23}$ found in the allowed $3 \sigma$ region. We also examine whether the parameter points consistent with neutrino oscillation data simultaneously comply with the experimental limits on lepton flavor violating (LFV) decays, specifically: $\mu \longrightarrow e \gamma$, $\tau \longrightarrow e \gamma$, and $\tau \longrightarrow \mu \gamma$. We have also investigated the matter-antimatter asymmetry of our universe via the resonant leptogenesis mechanism. Here, we present the contribution of lepton number conserving scattering processes mediated by the $ Z' $ boson in the context of leptogenesis.

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arXiv2025

Leptogenesis, $0\nu\beta\beta$ and lepton flavor violation in modular left-right asymmetric model with polyharmonic $Maa\beta$ forms

In the absence of supersymmetry, modular forms need not be holomorphic functions of the modulus $\tau$. Using this idea, we construct a non-supersymmetric framework using polyharmonic $Maa\beta$ forms. In this approach, the Yukawa coupling is no longer strictly holomorphic in $\tau$ but instead incorporates both holomorphic and non-holomorphic components. We realize a non-supersymmetric, left-right asymmetric model based on the $\Gamma_3$ modular group, where the active neutrino masses are generated via an extended inverse seesaw mechanism. The model successfully predicts the sum of neutrino masses below the current experimental bound and accommodates neutrino mixing angles within the $3\sigma$ range. Given its strong predictive power in neutrino oscillation parameters, we further explore its implications for beyond Standard Model (BSM) phenomena, including neutrinoless double beta ($0\nu\beta\beta$) decay, lepton flavor violation (LFV), and baryogenesis via leptogenesis (BAU). Our findings indicate that the model predicts an effective Majorana mass and LFV branching ratios consistent with experimental constraints while also providing a viable explanation for the observed baryon asymmetry through resonant leptogenesis.

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arXiv2025

Constraints on 1-0 texture through neutrino phenomenology and dark matter in minimal inverse seesaw

In this work we have realized texture zero structures of neutrino mass matrix through our study of neutrino phenomenology and dark matter. For analysing these processes, we have constructed a model in minimal inverse seesaw, ISS(2,3) by using $A_4$ discrete symmetry. The particle content of ISS(2.3) has been augmented by a scalar triplet $\eta=(\eta_1,\eta_2,\eta_3)$. The probable dark matter candidates for this model are the neutral components of $\eta$. The three mass matices of ISS(2,3), $M_D$, $M_{NS}$ and $M_S$ contribute to the structure of light neutrino mass matrix $m_\nu$. Here we try to examine the impact on texture structures of $m_\nu$ due to different possible 2-0 structures of $M_D$. To examine further possible contraints, we have evaluated the neutrino parameters and calculated relic density of dark matter for the favourable cases. From our analysis we find that out of the fifteen possible 2-0 structures, only two of them ($M_{D3}$ and $M_{D6}$) successfully generates all the mixing angles in the allowed ranges.

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arXiv2025

$keV$ sterile neutrino as dark matter in doublet left-right symmetric model with $A_{4}$ modular symmetry

Left-Right Symmetric Model(LRSM) in this work is extended with a sterile fermion per generation, the lightest of the same is considered to be a suitable dark matter candidate for the study and analysis of the associated properties. The model has been realized using $A_{4}$ modular symmetry, the advantage being the non-requirement of the use of extra fields, hence keeping the model minimal. Because of the extension of LRSM with the sterile fermion, the neutrino mass in this work will be generated by the double seesaw mechanism as described thoroughly within the manuscript. And for phenomenological studies, we have considered neutrinoless double beta decay the details of which have been discussed thoroughly within the work.

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arXiv2024

Neutrino mass genesis in Scoto-Inverse Seesaw with Modular $A_4$

We propose a hybrid scotogenic inverse seesaw framework in which the Majorana mass term is generated at the one-loop level through the inclusion of a singlet fermion. This singlet Majorana fermion also serves as a viable thermal relic dark matter candidate due to its limited interactions with other fields. To construct the model, we adopt an $A_4$ flavour symmetry in a modular framework, where the odd modular weight of the fields ensures their stability, and the specific modular weights of the couplings yield distinctive modular forms, leading to various phenomenological consequences. The explicit flavour structure of the mass matrices produces characteristic correlation patterns among the parameters. Furthermore, we examine several testable implications of the model, including neutrinoless double beta decay ($0\nu\beta\beta$), charged lepton flavour violation (cLFV), and direct detection prospects for the dark matter candidate. These features make our model highly testable in upcoming experiments.

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arXiv2024

Neutrino mass textures and associated phenomenology in modular left-right symmetric model

Neutrino mass textures play a crucial role in the study of various neutrino mass models and the associated phenomenology. The present work focuses on neutrino phenomenology in the framework of left-right symmetric model (LRSM) augmented by $A_4$ modular symmetry. More specifically we concentrated on the implementation of modular group of level 3 ($\Gamma(3)$). As the use of modular symmetry demands the assignment of different modular weights to the particle content of the model, we consider modular weights $k_Y$ = 4, 6, 8, 10 in LRSM which gives rise to different neutrino textures (texture zero structures) and study its consequent neutrino phenomenologies. Observables like resonant leptogenesis (RL), new physics contributions to neutrinoless double beta decay (NDBD)(momentum dependent ($\lambda$ and $\eta$) and right-handed neutrino contributions of NDBD and lepton flavor violation (LFV) has been deliberated. The study has been carried out for both normal and inverted ordering of neutrino mass and the correlations among the neutrino parameters for the present model has been elaborated for the TeV scale LRSM which can be tested in the experiments.

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arXiv2024

Study of Neutrino Phenomenology and $0\nu\beta\beta$ Decay using Polyharmonic $Maa\beta$ Forms

In this study, we explore the application of the $\Gamma_{3}$ modular group, which is isomorphic to the $A_{4}$ symmetric group in developing a model for neutrino mass. We realized a non-supersymmetric left-right asymmetric model incorporating modular symmetry, where the modular forms consist of both holomorphic and non-holomorphic components and the Yukawa couplings expressed through polyharmonic $Maa\beta$ forms. To effectively implement the extended see-saw process in this model, we introduce one fermion singlet for each generation. We compute the effective mass and the associated half-life of $0\nu\beta\beta$ by accounting for both standard and non-standard contributions. Additionally, our study investigates the non-unitary effects and CP-violation arising from non-unitarity in this context. The model predicts values for the sum of neutrino masses and neutrino oscillation parameters are constraints with experiments. Furthermore, it yields satisfactory results in calculating the effective mass and half-life of $0\nu\beta\beta$ decay. These findings highlight the possibility and benefit of employing modular symmetry in neutrino mass model construction.

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arXiv2024

$M_{W_R}$ dependence of leptogenesis in Minimal Left-Right Symmetric Model with different strengths of Type-II seesaw mass

Left Right Symmetric Model (LRSM) being an extension of the Standard model of particle physics incorporates within itself Type-I and Type-II seesaw mass terms naturally. Both the mass terms can have significant amount of contribution to the resulting light neutrino mass within the model and hence on the different phenomenology associated within. In this paper, we have thoroughly analyzed and discussed the implications of specifying different weightages to the type-I and type-II mass terms and also the study has been carried out for different values of $M_{W_R}$ which is mass of the right-handed gauge boson. This paper also gives a deeper insight into the new physics contributions of Neutrinoless Double Beta Decay $(0νββ)$ and their variations with the net baryon asymmetry arising out of the model. Therefore, the main objective of the present paper rests on investigating the implications of imposing different weightage to the type-I and type-II seesaw terms and different values of $M_{W_R}$ on the new physics contributions of $0νββ$ and net baryon asymmetry arising out as a result of resonant leptogenesis. LRSM in this work has been realized using modular group of level 3, $Γ(3)$ which is isomorphic to non-abelian discrete symmetry group $A_4$, the advantage being the non-requirement of flavons within the model and hence maintaining the minimality of the model.

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arXiv2023

Leptogenesis and dark matter in minimal inverse seesaw using $A_4$ modular symmetry

In this paper we have studied neutrino masses and mixings by adding a scalar triplet $η$ to the particle content of minimal inverse seesaw. We have realised this extension of minimal inverse seesaw by implementing an isomorphic modular group $Γ(3)$ and a non-abelian discrete symmetry group $A_4$. We have also used $Z_3$ symmetry group to restrain certain interaction terms in the lagrangian of the model. We have studied baryon asymmetry of the universe, neutrinoless double-beta decay and dark matter in our work. In order to check the consistency of our model with various experimental constraints, we have therefore calculated effective mass, relic density and baryogenesis via leptogenesis. Interestingly, we have found our model quite compatible with the experimental bounds and is also successful in producing the neutrino masses and mixings in the 3$σ$ range.

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arXiv2023

Connecting dark matter, baryogenesis and neutrinoless double beta decay in a $A_{4}\otimes Z_{8}$ based $ν$2HDM

In this paper, we discuss the impact of neutrino phenomenology and related cosmology on an $A_{4}\otimes Z_{8}$ symmetric $ν$2HDM along with an addition of a new particle, i.e. a gauge singlet(S). The additional particle is a sterile neutrino which is considered to be a probable dark matter candidate in our work. With the choice of sterile neutrino mass in keV range we evaluate the active-DM mixing angle, decay rate and relic abundance considering various cosmological constraints. Simultaneously, a detailed analysis on baryogenesis and neutrinoless double beta decay is also carried out for low scale right-handed neutrino masses. We have considered various bounds from experiments such as Lyman-$α$, X-ray observation, Planck data and KamLAND-Zen limit to validate the model w.r.t the phenomena studied in it.

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arXiv2023

Minimal Left-Right Symmetric Model with $A_4$ modular symmetry

In this paper, we have realized the left-right symmetric model with modular symmetry. We have used $Γ$(3) modular group which is isomorphic to non-abelian discrete symmetry group $A_4$. The advantage of using modular symmetry is the non-requirement for the use of extra particles called 'flavons'. In this model, the Yukawa couplings are expressed in terms of modular forms $(Y_1,Y_2,Y_3)$. In this work, we have studied minimal Left-Right Symmetric Model for both type-I and type-II dominances. Here, we have calculated the values for the Yukawa couplings and then plotted it against the sum of the neutrino masses. The results obtained are well within the experimental limits for the desired values of sum of neutrino masses. We have also briefly analyzed the effects of the implications of modular symmetry on neutrinoless double beta decay with the new physics contributions within Left-Right Symmetric Model.

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arXiv2022

Flavor symmetric origin of texture zeros in minimal inverse seesaw and impacts on leptogenesis

We study the prediction of maximal zeros of the Dirac mass matrix on neutrino phenomenology and baryon asymmetry of the universe (BAU) within the framework of an inverse seesaw ISS $(2,3)$. We try to find the origin of the allowed two zero textures of the Dirac mass matrix from $S_{4}$ flavor symmetry. ISS $(2,3)$ model contains two pairs of quasi-Dirac particles and one sterile state in the keV scale along with three active neutrinos. The decays of the quasi-Dirac pairs create lepton asymmetry that can be converted to baryon asymmetry of the universe by the sphaleron process. Thus, BAU can be explained in this framework through leptogenesis. We study BAU in all the two zero textures of the Dirac mass matrix. The viabilities of the textures within the framework have been verified with the latest cosmology data on BAU.

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arXiv2022

Neutrino masses and mixing in Minimal Inverse Seesaw using $A_4$ modular symmetry

In this paper, we construct a model with the help of modular symmetry in the framework of minimal inverse seesaw [ISS(2,3)]. We have used $Γ(3)$ modular group which is isomorphic to non-Abelian discrete symmetry group $A_4$. In this group there are three Yukawa modular forms of weight 2. Through this model, we study neutrino masses and mixing for both normal and inverted hierarchy. Use of modular symmetry reduces the need for extra flavons and their specific VEV alignments, as such, minimality of the model is maintained to a great extent. Along with $A_4$ symmetry group, we have used $Z_3$ to restrict certain interaction terms in the Lagrangian. Further we calculate the effective mass to address the phenomena of neutrinoless double-beta decay ($0νββ$). The values of effective mass is found to lie within the bound ($m_{eff}<0.165$ eV) as predicted by different $0νββ$ experiments.

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