arXiv subjects

Mrinal Kumar Das

Publications and source records attributed to Mrinal Kumar Das.

At least 37 records · Page 2Linked to original sources

arXiv2022

Neutrinoless double beta decay and Sterile dark matter in extended left right symmetric model

We have studied a flavor symmetry-based extended left-right symmetric model(LRSM) with a dominant type-II seesaw mechanism and have explored the associated neutrino phenomenology. The particle content of the model includes usual quarks, and leptons along with additional sterile fermion per generation in the fermion sector while the scalar content contains Higgs doublets and scalar bidoublet. Realization of this extension of LRSM has been done by using $A_{4}\times Z_{4}$ discrete symmetries. In this work, we have also included the study of sterile neutrino dark matter(DM) phenomenology along with neutrinoless double beta decay within the framework.

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arXiv2022

Dark matter and low scale leptogenesis in a flavor symmetric neutrino two Higgs doublet model($ν$2HDM)

We have studied dark matter (DM) phenomenology, neutrinoless double beta decay (NDBD) and realized low scale leptogenesis in an extension of Standard Model(SM) with three neutral fermions, a scalar doublet and a dark sector incorporating a singlet scalar and a Dirac singlet fermion. A generic model based on $A_4\times Z_4$ flavor symmetry including five flavons is used to explain both normal and inverted hierarchy mass patterns of neutrino and also to accommodate the dark matter mass. In this extension of the $ν$2HDM, the effective neutrino mass observed in $0νββ$ is well within the experimental limit provided by KamLAND-ZEN. In order to validate DM within this model, we have checked relic abundance and free streaming length of the dark sector component, i.e. a Dirac singlet fermion constraining its mass in keV range. More importantly we have also realised low scale leptogenesis simultaneously within this framework and also the Dirac CP phase gets constrained with the results. Bound from LFV is also incorporated in order to constrain the Yukawa couplings. More importantly, we have analyzed the dependence of various phenomenology with decay parameter for different choice of arbitrary complex angles.

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arXiv2022

Phenomenology of one zero texture Yukawa matrix in a flavor symmetric scotogenic model

The scotogenic model is well known for accommodating small neutrino mass and dark matter. Here, we have realized the scotogenic model with the help of discrete flavor symmetry $A_{4}\otimes Z_{4}$. We have obtained three one zero textures of Yukawa coupling matrices from the model and have studied its impact on neutrino phenomenology and related aspects of cosmology. On the basis of $μ-τ$ symmetry, we have further discarded two structures of one zero texture Yukawa coupling matrix. We further analyze if the effective mass of active neutrinos obtained by the virtue of the Yukawa coupling matrix is consistent with the KamLAND-Zen limit for 0$νββ$. Also different lepton flavor violating(LFV) processes such as $l_α\longrightarrow l_βγ$ and $l_α\longrightarrow 3l_β$ are implemented and their influence on neutrino phenomenology is studied corresponding to the Yukawa coupling matrix. The entire work is carried out considering the dark matter mass($M_{DM}$) in the region $450-750$ GeV. We have also obtained some significant results for baryon asymmetry of the Universe in agreement with the one zero textures of the coupling matrices. Furthermore, interesting results for relic abundance on the basis of distinct mass splittings between the inert scalars.

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arXiv2022

Five-zero texture in neutrino-dark matter model within the framework of minimal extended seesaw

We study a model of neutrino and dark matter within the framework of a minimal extended seesaw. This model is based on $A_4$ flavour symmetry along with the discrete $Z_3\times Z_4$ symmetry to stabilize the dark matter and construct desired mass matrices for neutrino mass. Five-zero textures are imposed in the final $4\times4$ active-sterile mass matrix, which significantly reduces free parameter in the model. Three right-handed neutrinos were considered, two of them have nearly degenerate masses which help us to achieve baryogenesis via resonant leptogenesis. A singlet fermion (sterile neutrino) with mass $\sim\mathcal{O}$(eV) is also considered, and we are able to put bounds on active-sterile mixing parameters via neutrino oscillation data. Resonant enhancement of lepton asymmetry is studied at TeV scale, where we discuss a few aspects of baryogenesis considering the flavour effects. Possibility of improvement in effective mass from $0νββ$ in the presence of a single generation of sterile neutrino flavour is also studied within the fermion sector. In the scalar sector, the imaginary component of the complex singlet scalar is behaving as a potential dark matter candidate and simultaneously the real part of the complex scalar is associated with the fermion sector for sterile mass generation. A broad region of dark matter mass is analyzed from various annihilation processes, and the VEV of the complex scalar plays a pivotal role to achieve the observed relic density at the right ballpark.

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arXiv2022

The FIMP-WIMP dark matter in the extended singlet scalar model

We explore the simplest viable dark matter model with a real singlet scalar, vector-like singlet and doublet fermions. The Yukawa couplings associated with the fermion sector play a crucial role in getting the current relic density through Freeze-in and Freeze-out mechanism. We discuss the constraints from the recent muon anomalous magnetic moment experimental data and relic density. We also perform the collider analysis for the FIMP dark matter in the context of 14 TeV LHC experiments with the MATHUSLA100/200 detector. Our analysis shows that one can get enough events $>3$ for heavy charged fermion track at 14 TeV LHC with an integrated luminosity $\mathcal{L}=10^6 ~{\rm fb^{-1}}$.

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arXiv2022

Neutrinoless double-beta decay and lepton flavor violation in discrete flavor symmetric left-right symmetric model

In this work, we have studied neutrino less double beta decay(NDBD) and charged lepton flavor violation(CLFV) in a generic Left-Right symmetric model (LRSM). In this framework, type-I and type-II seesaw terms arise naturally. We have used $A_{4}\times Z_{2}$ discrete flavor symmetry to realize the LRSM. Within the model, we have considered type-I and type-II dominant cases and analyzed the new physics contributions to the NDBD process coming from different particles of LRSM. We tried to find the leading order contributions to NDBD in type-I and type-II seesaw along with the decay rate of the process in our work. We have also studied different charged lepton flavor violating processes such as $μ\rightarrow 3e$ and $μ\rightarrow e γ$ and correlated with neutrino mass within the model.

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arXiv2021

FIMP DM in the Extended Hyperchargeless Higgs Triplet Model

We perform an exclusive study on the Feebly Interacting Massive Particle (FIMP) dark matter candidate in an extended hyperchargeless ($Y=0$) Higgs triplet model. The additional $Z_2$ odd neutral fermion singlet plays the role of dark matter with support from two other vector-like fermion doublets. The mixing between the neutral component of a doublet and singlet fermions controls the current relic density through the Freeze-in mechanism, whereas the additional doublet fermion helps to get the neutrino mass and mixing angles. We obtain a broad region of the parameter spaces satisfying the current relic density and neutrino mass and mixing angles.

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arXiv2021

Impact of texture zeros on dark matter and neutrinoless double beta decay in inverse seesaw

We study the impact of maximal zeros of the Dirac mass matrix on neutrino phenomenology and dark matter within the framework of an inverse seesaw ISS $(2,3)$. ISS $(2,3)$ is obtained by adding two right handed neutrinos and three gauge singlets sterile fermions to the standard model leading to an extra sterile state in the keV range. The model is more predictive because of the presence of fewer numbers of right handed neutrinos than the conventional inverse seesaw. Moreover, texture zeros in the structures of the mass matrices involved in the model can reduce the free parameters. We extensively study the effect of different textures of Dirac mass matrix on sterile neutrino dark matter phenomenology. Our study also includes the implications of these texture zero mass matrices on low energy phenomena like neutrinoless double beta decay (0$νββ$). The zero textures highly constrain the parameter space of the model. Based on the allowed cosmological ranges of the relic abundance, decay rates, and dark matter mixing with the active neutrinos, we study the viability of the different textures within the framework.

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arXiv2021

Neutrino mass, leptogenesis and sterile neutrino dark matter in inverse seesaw framework

We study $S_{4}$ flavor symmetric inverse seesaw model which has the possibility of simultaneously addressing neutrino phenomenology, dark matter (DM) and baryon asymmetry of the universe (BAU) through leptogenesis. The model is the extension of the standard model by the addition of two right handed neutrinos and three sterile fermions leading to a keV scale sterile neutrino dark matter and two pairs of quasi-Dirac states. The CP violating decay of the lightest quasi- Dirac pair present in the model generates lepton asymmetry which then converts to baryon asymmetry of the universe. Thus this model can provide a simultaneous solution for non zero neutrino mass, dark matter content of the universes and the observed baryon asymmetry. The $S_{4}$ flavor symmetry in this model is augmented by additional $Z_{4}\times Z_{3}$ symmetry to constrain the Yukawa Lagrangian. A detailed numerical analysis has been carried out to obtain dark matter mass, DM-active mixing as well as BAU both for normal hierarchy as well as inverted hierarchy. We have tried to correlate the two cosmological observables and found a common parameter space satisfying the DM phenomenology and BAU. The parameter space of the model is further constrained from the latest cosmological bounds on the above mentioned observables.

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arXiv2021

Lepton flavor violation and leptogenesis in discrete flavor symmetric scotogenic model

We have studied the scotogenic model proposed by Ernest Ma, which is an extension of the Standard Model by three singlet right-handed neutrinos and a scalar doublet. This model proposes that the light neutrinos acquire a non-zero mass at 1-loop level. In this work, the realisation of the scotogenic model is done by using discrete symmetries $A_{4}\times Z_{4}$ in which the non-zero $θ_{13}$ is produced by assuming a non-degeneracy in the loop factor. Considering different lepton flavor violating(LFV) processes such as $l_α\longrightarrow l_βγ$ and $l_α\longrightarrow 3l_β$, their impact on neutrino phenomenology is studied. We have also analysed $0νββ$ and baryon asymmetry of the Universe (BAU) in this work.

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arXiv2021

A new feasible dark matter region in the singlet scalar scotogenic model

We study a simplest viable dark matter model with a real singlet scalar, vector-like singlet and a doublet lepton. We find a considerable enhancement in the allowed region of the scalar dark matter parameter spaces under the influence of the new Yukawa coupling. The Yukawa coupling associate with the fermion sector heavily dominant the dark matter parameter spaces satisfying the current relic density of the Universe. Dilepton$+\slashed{E}_T$ signature arising from the new fermionic sector can observe at Large Hadron Collider (LHC). We perform such analysis in the context of 14 TeV LHC experiments with a future integrated luminosity of 3000 ${\rm fb^{-1}}$. We found that a large region of the parameter spaces can be probed by the LHC experiments. The projected exclusion/discovery reach of direct heavy charged fermion searches in this channels is analyzed by performing a detailed cut based collider analysis. The projected exclusion contour reaches up to $1050-1380~{\rm GeV}$ for 3000 ${\rm fb^{-1}}$ for a light dark matter $\mathcal{O}(10)$ GeV from searches in the $ pp \rightarrow E_1^\pm E_1^\mp, E_1^\pm\rightarrow l^\pm S \rightarrow ll + \slashed{E}_T$ channel.

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arXiv2020

Scalar dark matter and leptogenesis in the minimal scotogenic model

We study the minimal scotogenic model constituting an additional inert Higgs doublet and three sets of right-handed neutrinos. The scotogenic model connects dark matter, baryon asymmetry of the Universe and neutrino oscillation data. In our work, we obtain baryogenesis by the decay of TeV scale heavy neutral singlet fermion ($N_{2}$). We primarily focus on the intermediate-mass region of dark matter within $M_W<M_{DM}\le550$ GeV, where observed relic density is suppressed due to co-annihilation processes. We consider thermal as well as the non-thermal approach of dark matter production and explore the possibility of the lightest stable candidate being a dark matter candidate. Within the inert Higgs doublet (IHD) desert, we explore a new allowed region of dark matter masses for the non-thermal generation of dark matter with a mass splitting of 10 GeV among the inert scalars. We also see the variation of relic abundance for unequal mass splitting among the scalars. The KamLand-Zen bound on the effective mass of the active neutrinos is also verified in this study.

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arXiv2020

Effect of sterile neutrino on low energy processes in minimal extended seesaw with $Δ(96)$ symmetry and $\text{TM}_{1}$ mixing

We study the effect of sterile neutrino on some low scale processes in the framework of minimal extended seesaw (MES). MES is the extension of the seesaw mechanism with the addition of sterile neutrino of intermediate mass. The MES model in this work is based on $Δ(96)\times C_{2}\times C_{3}$ flavor symmetry. The structures of mass matrices in the framework lead to $TM_{1}$ mixing with $μ\text{-}τ$ symmetry. The model predicts maximal value of Dirac CP phase. We carry out our analysis to study the new physics contributions from the sterile neutrino to different charged lepton flavor violation (cLFV) processes involving muon and tau leptons as well as neutrinoless double beta decay (0$νββ$). The model predicts normal ordering (NO) of neutrino masses and we perform the numerical analysis considering normal ordering (NO) only. We find that sterile neutrino mass in GeV range can lead to cLFV processes that are within the reach of current and planned experiments. The GeV scale sterile neurtrino in our model is consistent with the current limits on the effective neutrino mass set by $0νββ$ experiments.

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arXiv2020

Phenomenology of $keV$ sterile neutrino in minimal extended seesaw

We explore the possibility of a single generation of $keV$ scale sterile neutrino ($m_S$) as a dark matter candidate within the minimal extended seesaw (MES) framework and it's influence in neutrinoless double beta decay ($0νββ$) study. Three hierarchical right-handed neutrinos were considered to explain neutrino mass. We also address baryogenesis via the mechanism of thermal leptogenesis considering the decay of the lightest RH neutrino to a lepton and Higgs doublet. A generic model based on $A_4\times Z_4\times Z_3$ flavor symmetry is constructed to explain both normal and inverted hierarchy mass pattern of neutrinos. Significant results on effective neutrino masses are observed in presence of sterile mass ($m_S$) and active-sterile mixing ($θ_{S}$) in $0νββ$. Results from $0νββ$ give stringent upper bounds on the active-sterile mixing matrix element. To establish sterile neutrino as dark matter within this model, we checked decay width and relic abundance of the sterile neutrino, which restricted sterile mass ($m_S$) within some definite bounds. Constrained regions on the CP-phases and Yukawa couplings are obtained from $0νββ$ and baryogenesis results. Co-relations among these observable are also established and discussed within this framework.

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arXiv2020

Phenomenological study of texture zeros of neutrino mass matrix in minimal left-right symmetric model

We studied the phenomenological implications of texture zeros in the neutrino mass matrix of the minimal left-right symmetric model (LRSM). Since the possibility of maximum zeros reduces the maximum number of free parameters of the model making it more predictive, we considered only those cases with maximum possible texture zeros in light neutrino mass matrix $M_ν$, Dirac neutrino mass matrix $M_D$ and heavy right-handed (RH) neutrino mass matrix $M_{RR}$. We then computed the correlations among the different light neutrino parameters and then the new physics contributions to neutrinoless double beta decay (NDBD) for the different texture zero cases. We find that for RH neutrino masses above 1 GeV, the new physics contributions to NDBD can saturate the corresponding experimental bound.

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arXiv2020

Phenomenological study of neutrino mass, dark matter and baryogenesis within the framework of minimal extended seesaw

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 matrices for neutrino mass. We use a non-trivial Dirac mass matrix with broken $μ- τ$ symmetry to generate the leptonic mixing. A non-degenerate mass structure for right-handed neutrinos is considered to verify the observed baryon asymmetry of the Universe via the mechanism of thermal Leptogenesis. The scalar sector is also studied in great detail for a multi-Higgs doublet scenario, considering the lightest $Z_4$-odd as a viable dark matter candidate. A significant impact on the region of DM parameter space, as well as in the fermionic sector, are found in the presence of extra scalar particles.

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arXiv2019

Phenomenology of keV scale sterile neutrino dark matter with $S_{4}$ flavor symmetry

We study the possibility of simultaneously addressing neutrino phenomenology and the dark matter in the framework of inverse seesaw. The model is the extension of the standard model by the addition of two right handed neutrinos and three sterile fermions which leads to a light sterile state with the mass in the keV range along with three light active neutrino states. The lightest sterile neutrino can account for a feasible dark matter(DM) candidate. We present a $S_{4}$ flavor symmetric model which is further augmented by $Z_{4}\times Z_{3}$ symmetry to constrain the Yukawa Lagrangian. The structures of the mass matrices involved in inverse seesaw within the $S_{4}$ framework naturally give rise to correct neutrino mass matrix with non-zero reactor mixing angle $ θ_{13}$. In this framework, we conduct a detailed numerical analysis both for normal hierarchy as well as inverted hierarchy to obtain dark matter mass and DM-active mixing which are the key factors for considering sterile neutrino as a viable dark matter candidate. We constrain the parameter space of the model from the latest cosmological bounds on the mass of the dark matter and DM-active mixing.

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arXiv2019

Phenomenological Study of Texture Zeros in Lepton Mass Matrices of Minimal Left-Right Symmetric Model

We consider the possibility of texture zeros in lepton mass matrices of the minimal left-right symmetric model (LRSM) where light neutrino mass arises from a combination of type I and type II seesaw mechanisms. Based on the allowed texture zeros in light neutrino mass matrix from neutrino and cosmology data, we make a list of all possible allowed and disallowed texture zeros in Dirac and heavy neutrino mass matrices which appear in type I and type II seesaw terms of LRSM. For the numerical analysis we consider those cases with maximum possible texture zeros in light neutrino mass matrix $M_ν$, Dirac neutrino mass matrix $M_D$, heavy neutrino mass matrix $M_{RR}$ while keeping the determinant of $M_{RR}$ non-vanishing, in order to use the standard type I seesaw formula. The possibility of maximum zeros reduces the free parameters of the model making it more predictive. We then compute the new physics contributions to rare decay processes like neutrinoless double beta decay, charged lepton flavour violation. We find that even for a conservative lower limit on a left-right symmetry scale corresponding to heavy charged gauge boson mass 4.5 TeV, in agreement with collider bounds, for right-handed neutrino masses above 1 GeV, the new physics contributions to these rare decay processes can saturate the corresponding experimental bound.

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