Drona Vatsyayan
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View article: The Generalised Casas-Ibarra Parametrisation for Majorana Neutrino Masses
The Generalised Casas-Ibarra Parametrisation for Majorana Neutrino Masses Open
We present a simple and broadly applicable extension of the Casas-Ibarra parametrisation that captures the structure of all Majorana neutrino mass models. Building directly on the original formulation, our approach naturally accommodates a…
View article: Large neutrino mass in cosmology and keV sterile neutrino dark matter from a dark sector
Large neutrino mass in cosmology and keV sterile neutrino dark matter from a dark sector Open
We consider an extended seesaw model which generates active neutrino masses via the usual type-I seesaw and leads to a large number of massless fermions as well as a sterile neutrino dark matter (DM) candidate in the 𝒪(10–100) keV mass ran…
View article: Large neutrino mass in cosmology and keV sterile neutrino dark matter from a dark sector
Large neutrino mass in cosmology and keV sterile neutrino dark matter from a dark sector Open
We consider an extended seesaw model which generates active neutrino masses via the usual type-I seesaw and leads to a large number of massless fermions as well as a sterile neutrino dark matter (DM) candidate in the $\mathcal{O}(10-100) {…
View article: Neutrino masses from new seesaw models: low-scale variants and phenomenological implications
Neutrino masses from new seesaw models: low-scale variants and phenomenological implications Open
With just the Standard Model Higgs doublet, there are only three types of seesaw models that generate light Majorana neutrino masses at tree level after electroweak spontaneous symmetry breaking. However, if there exist additional TeV scal…
View article: Leptogenesis, dark matter and gravitational waves from discrete symmetry breaking
Leptogenesis, dark matter and gravitational waves from discrete symmetry breaking Open
We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator Φ, stabilised by a discrete 𝒵 4 symmetry that breaks to a remnant 𝒵 2 upon Φ acquiring a non-zero vacuum expectation value ( v ϕ ). The…
View article: Neutrino masses from new Weinberg-like operators: phenomenology of TeV scalar multiplets
Neutrino masses from new Weinberg-like operators: phenomenology of TeV scalar multiplets Open
A bstract The unique dimension-5 effective operator, LLHH , known as the Weinberg operator, generates tiny Majorana masses for neutrinos after electroweak spontaneous symmetry breaking. If there are new scalar multiplets that take vacuum e…
View article: Neutrino masses and unitarity violation from higher SU(2) representations
Neutrino masses and unitarity violation from higher SU(2) representations Open
The Weinberg operator is the unique dimension-5 operator that generates Majorana masses for\nneutrinos after electroweak symmetry breaking. Thus, it seems natural that the way to have\nsmall neutrino masses is that they are Majorana partic…
View article: Leptogenesis, Dark Matter and Gravitational Waves from Discrete Symmetry Breaking
Leptogenesis, Dark Matter and Gravitational Waves from Discrete Symmetry Breaking Open
We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator $Φ$, stabilised by a discrete $Z_4$ symmetry that breaks to a remnant $Z_2$ upon $Φ$ acquiring a non-zero vacuum expectation value ($v_…
View article: Neutrino masses from new seesaw models: Low-scale variants and phenomenological implications
Neutrino masses from new seesaw models: Low-scale variants and phenomenological implications Open
With just the Standard Model Higgs doublet, there are only three types of seesaw models that generate light Majorana neutrino masses at tree level after electroweak spontaneous symmetry breaking. However, if there exist additional TeV scal…
View article: Neutrino masses from new Weinberg-like operators: Phenomenology of TeV scalar multiplets
Neutrino masses from new Weinberg-like operators: Phenomenology of TeV scalar multiplets Open
The unique dimension-$5$ effective operator, $LLHH$, known as the Weinberg operator, generates tiny Majorana masses for neutrinos after electroweak spontaneous symmetry breaking. If there are new scalar multiplets that take vacuum expectat…
View article: Asymmetries in extended dark sectors: a cogenesis scenario
Asymmetries in extended dark sectors: a cogenesis scenario Open
A bstract The observed dark matter relic abundance may be explained by different mechanisms, such as thermal freeze-out/freeze-in, with one or more symmetric/asymmetric components. In this work we investigate the role played by asymmetries…
View article: Lowering the scale of fermion triplet leptogenesis with two Higgs doublets
Lowering the scale of fermion triplet leptogenesis with two Higgs doublets Open
In this paper, we consider the possibility of generating the observed baryon asymmetry of the Universe via leptogenesis in the context of a triplet fermion-mediated type-III seesaw model of neutrino mass. With a hierarchical spectrum of th…
View article: Asymmetries in Extended Dark Sectors: A Cogenesis Scenario
Asymmetries in Extended Dark Sectors: A Cogenesis Scenario Open
The observed dark matter relic abundance may be explained by different mechanisms, such as thermal freeze-out/freeze-in, with one or more symmetric/asymmetric components. In this work we investigate the role played by asymmetries in determ…
View article: Multi-component dark sectors: symmetries, asymmetries and conversions
Multi-component dark sectors: symmetries, asymmetries and conversions Open
View article: Symmetry origin of baryon asymmetry, dark matter, and neutrino mass
Symmetry origin of baryon asymmetry, dark matter, and neutrino mass Open
We propose a minimal model based on lepton number symmetry (and violation), to address a common origin of baryon asymmetry, dark matter and neutrino mass generation. The model consists of a vectorlike fermion to constitute the dark sector,…
View article: Lowering the scale of fermion triplet leptogenesis with two Higgs doublets
Lowering the scale of fermion triplet leptogenesis with two Higgs doublets Open
In this paper, we consider the possibility of generating the observed baryon asymmetry of the Universe via leptogenesis in the context of triplet fermion mediated type-III seesaw model of neutrino mass. With a hierarchical spectrum of the …
View article: Symmetry origin of Baryon Asymmetry, Dark Matter and Neutrino Mass
Symmetry origin of Baryon Asymmetry, Dark Matter and Neutrino Mass Open
We propose a minimal model based on lepton number symmetry (and violation), to address a common origin of baryon asymmetry, dark matter and neutrino mass generation. The model consists of a vector like fermion to constitute the dark sector…
View article: Constraints on the quark mixing matrix with vector-like quarks
Constraints on the quark mixing matrix with vector-like quarks Open