arXiv subjects

Lavina Sarma

Publications and source records attributed to Lavina Sarma.

6 recordsLinked to original sources

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.

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗

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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