arXiv subjects

Newton Nath

Publications and source records attributed to Newton Nath.

At least 37 records · Page 2Linked to original sources

arXiv2021

Flavored axion in the UV-complete Froggatt-Nielsen models

We propose UV-completions of Froggatt-Nielsen-Peccei-Quinn models of fermion masses and mixings with flavored axions, by incorporating heavy fields. Here, the $U(1)$ Froggatt-Nielsen symmetry is identified with the Peccei-Quinn symmetry to solve the strong CP problem along with the mass hierarchies of the Standard Model fermions. We take into account leading order contributions to the fermion mass matrices giving rise to Nearest-Neighbour-Interaction structure in the quark sector and $A_2$ texture in the neutrino sector. A comprehensive numerical analysis has been performed for the fermion mass matrices. Subsequently, we investigate the resulting axion flavor violating couplings and the axion-photon coupling arising from the model.

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arXiv2020

RGE-induced $μ$-$τ$ symmetry breaking: an analysis of the latest T2K results

The T2K collaboration has recently reported their results, which gives the best-fit values of the atmospheric mixing angle $\sin^2 θ_{23} = 0.53$ and the Dirac CP-violating phase $δ= -1.89$ for normal neutrino mass ordering. We give a possible theoretical origin of such values based on the $μ$-$τ$ reflection symmetry. It has been found that the breaking of such symmetry using one-loop renormalization-group equations (RGEs) in the framework of minimal supersymmetric standard model can fit well with the latest T2K results and the recent global fits. To make a quantitative analysis, we have included for the first time the complete dataset of oscillation, beta decay, neutrinoless double-beta decay and cosmological observations in comparing the theory to experiments. We also further examine the importance of such breaking patterns for neutrinoless double-beta decay experiments.

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arXiv2020

Neutrino phenomenology in a left-right $D_4$ symmetric model

We present a minimal left-right symmetric flavor model and analyze the predictions for the neutrino sector. In this scenario, the Yukawa sector is shaped by the dihedral $D_4$ symmetry which leads to correlations for the neutrino mixing parameters. We end up with four possible solutions within this model. We further analyzed the impact of the upcoming long-baseline neutrino oscillation experiment DUNE. Due to its high sensitivity, DUNE will be able to rule out two of the solutions. Finally, the prediction for the neutrinoless double beta decay for the model has also been examined.

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arXiv2020

Probing the predictions of an orbifold theory of flavor

We examine the implications of a recently proposed theory of fermion masses and mixings in which an $A_4$ family symmetry emerges from orbifold compactification. We analyse two variant schemes concerning their predictions for neutrino oscillations, neutrinoless double-beta decay and the golden quark-lepton unification mass relation. We find that upcoming experiments DUNE as well as LEGEND and nEXO offer good chances of exploring a substantial region of neutrino parameters.

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arXiv2020

Dirac neutrinos from Peccei-Quinn symmetry: two examples

We aim to explain the nature of neutrinos using Peccei-Quinn symmetry. We discuss two simple scenarios, one based on a type-II Dirac seesaw and the other in a one-loop neutrino mass generation, which solve the strong CP problem and naturally lead to Dirac neutrinos. In the first setup latest neutrino mass limit gives rise to axion which is in the reach of conventional searches. Moreover, we have both axion as well as WIMP dark mater for our second set up.

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arXiv2020

Nonstandard neutrino interactions and mu-tau reflection symmetry

Nonstandard interactions (NSIs), possible subleading effects originating from new physics beyond the Standard Model, may affect the propagation of neutrinos and eventually contribute to measurements of neutrino oscillations. Besides this, $ μ-τ$ reflection symmetry, naturally predicted by non-Abelian discrete flavor symmetries, has been very successful in explaining the observed leptonic mixing patterns. In this work, we study the combined effect of both. We present an $S_4$ flavor model with $μ-τ$ reflection symmetry realized in both neutrino masses and NSIs. Under this formalism, we perform a detailed study for the upcoming neutrino experiments DUNE and T2HK. Our simulation results show that under the $μ-τ$ reflection symmetry, NSI parameters are further constrained and the mass ordering sensitivity is less affected by the presence of NSIs.

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arXiv2020

Non-standard neutrino interactions in $U(1)'$ model after COHERENT data

We explore the potential to prove light extra gauge $Z^\prime$ boson inducing non-standard neutrino interactions (NSIs) in the coherent-elastic neutrino-nucleus scattering (CE$ ν$NS) experiments. We intend to examine how the latest COHERENT-CsI and CENNS-10 data can constrain this model. A detailed investigation for the upcoming Ge, LAr-1t, and NaI detectors of COHERENT collaboration has also been made. Depending on numerous other constraints coming from oscillation experiments, muon $ (g-2) $, beam-dump experiments, LHCb, and reactor experiment CONUS, we explore the parameter space in $Z^\prime$ boson mass vs coupling constant plane. Moreover, we study the predictions of two-zero textures that are allowed in the concerned model in light of the latest global-fit data.

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arXiv2019

Breaking of the tetra-maximal neutrino mixing pattern

We make an attempt to study the present status of the tetra-maximal neutrino mixing (TMM) pattern. It predicts all the three leptonic mixing angles $θ_{13} \approx 8.4^\circ, θ_{12} \approx 30.4^\circ, $ and $θ_{23} = 45^\circ $ together with the three CP-violating phases $ - δ= ρ= σ= 90^\circ $. However, the latest global analysis of neutrino oscillation data prefer relatively higher best-fit value of $ θ_{12} $ as well as non-maximal values of both $ θ_{23}, δ$. In order to explain the realistic data, we study the breaking of TMM pattern. We first examine the breaking of TMM due to renormalization group (RG) running effects and then study the impact of explicit breaking terms. We also examine the effect of RG-induced symmetry breaking on the effective Majorana neutrino mass in neutrinoless double beta decay experiments.

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arXiv2019

$ μ-τ$ Reflection Symmetry and Its Explicit Breaking for Leptogenesis in a Minimal Seesaw Model

The minimal seesaw framework, embroiling the Dirac neutrino mass matrix $ M_D $ and the Majorana neutrino mass matrix $ M_R $, is quite successful to explain the current global-fit results of neutrino oscillation data. In this context, we consider most predictive forms of $ M_D $ and $ M_R $ with two simple parameters, respectively. Considering these matrices, we obtain the low energy neutrino mass matrix under type-I seesaw formalism which obeys $ μ-τ$ reflection symmetry and predicts $ θ_{23} = π/4$ and $ δ= \pm π/2 $. In the given set-up, we also evaluate the Baryon Asymmetry of the Universe (BAU) through successful leptogenesis and find that perturbation of $ \mathcal{O}(10^{-2}) $ leads to the observed BAU and breaks exactness of the symmetry. Moreover, we also perform various correlation studies among different parameters in the framework of broken symmetry.

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arXiv2019

Status and prospects of `bi-large' leptonic mixing

Bi-large patterns for the leptonic mixing matrix are confronted with current neutrino oscillation data. We analyse the status of these patterns and determine, through realistic simulations, the potential of upcoming long-baseline experiment DUNE in testing bi-large \emph{ansatze} and discriminating amongst them.

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arXiv2019

Testing generalized CP symmetries with precision studies at DUNE

We examine the capabilities of the DUNE experiment in probing leptonic CP violation within the framework of theories with generalized CP symmetries characterized by the texture zeros of the corresponding CP transformation matrices. We investigate DUNE's potential to probe the two least known oscillation parameters, the atmospheric mixing angle $θ_{23}$ and the Dirac CP-phase $δ_{\rm CP}$. We fix theory-motivated benchmarks for ($ \sin^2θ_{23}, δ_{\rm CP} $) and take them as true values in our simulations. Assuming 3.5 years of neutrino running plus 3.5 years in the antineutrino mode, we show that in all cases DUNE can significantly constrain and in certain cases rule out the generalized CP texture zero patterns.

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arXiv2019

Impact of RGE-induced $ μ-τ$ Reflection Symmetry Breaking on the Effective Majorana Neutrino Mass in $ 0νββ$ Decay

We make an attempt to study the impact of renormalization-group equations (RGE) induced $μ-τ$ reflection symmetry breaking on the effective Majorana neutrino mass $ |\langle m\rangle_{ee} | $ in neutrinoless double beta ($ 0νββ$) decay. At present, the $ 0νββ$ decay serves as a unique process to address the Majorana nature of massive neutrinos. The rate of such decay process depends on $ |\langle m\rangle_{ee} | $. On the other hand, $μ-τ$ reflection symmetry predicts $ θ_{23} = 45^\circ$ and $ δ= \pm 90^\circ $ together with trivial values of the Majorana CP-phases ($ ρ, σ$). Moreover, based on the recent global best-fit values which prefer higher octant of $ θ_{23} $ and third quadrant of $ δ$, it is hard to believe the exactness of such symmetry. Also, any non-trivial values of $ ρ, σ$ may have some significant impact on $ |\langle m\rangle_{ee} | $. In this context, we study the spontaneous breaking of the symmetry via one-loop RGE-running from a superhigh energy scale ($Λ_{μτ} $) down to the electroweak scale ($ Λ_{\rm EW} $). Given the broken symmetry, we perform some systematic analysis for $ |\langle m\rangle_{ee} | $ in substantial detail. Further, we also extend this analysis for other lepton-number violating effective Majorana masses.

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arXiv2019

Exploring Partial $μ$-$τ$ Reflection Symmetry at DUNE and Hyper-Kamiokande

We study origin, consequences and testability of a hypothesis of `partial $μ$-$τ$' reflection symmetry. This symmetry predicts $ |U_{μi}|=|U_{τi}|~(i=1,2,3) $ for a single column of the leptonic mixing matrix $U$. Depending on whether this symmetry holds for the first or second column of $U$ different correlations between $θ_{23}$ and $ δ_{CP} $ can be obtained. This symmetry can be obtained using discrete flavour symmetries. In particular, all the subgroups of SU(3) with 3-dimensional irreducible representation which are classified as class C or D can lead to partial $μ$-$τ$ reflection symmetry. We show how the predictions of this symmetry compare with the allowed area in the $\sin^2θ_{23} - δ_{CP}$ plane as obtained from the global analysis of neutrino oscillation data. Furthermore, we study the possibility of testing these symmetries at the proposed DUNE and Hyper-Kamiokande (HK) experiments (T2HK, T2HKK), by incorporating the correlations between $θ_{23}$ and $ δ_{CP}$ predicted by the symmetries. We find that when simulated data of DUNE and HK is fitted with the symmetry predictions, the $θ_{23}-δ_{CP}$ parameter space gets largely restricted near the CP conserving values of $ δ_{CP} $. Finally, we illustrate the capability of these experiments to distinguish between the two cases leading to partial $μ-τ$ symmetry namely $|U_{\mu1}| = |U_{τ1}|$ and $|U_{μ2}| = |U_{τ2}|$.

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arXiv2018

Consequences of $ μ-τ$ Reflection Symmetry at DUNE

We consider minimal type-I seesaw framework to realize $ μ-τ$ reflection symmetry in the low-energy neutrino mass matrix, $ M_ν $. Considering DUNE experiment, we scrutinize its potential to measure the precision of 2-3 mixing angle, $ θ_{23} $ and the Dirac CP-phase, $ δ$ for the given symmetry. Later, we examine the precision of these two parameters considering NuFit-3.2 data as one of the important true points. To study the low-energy phenomenology, we further discuss various breaking patterns of such an exact symmetry. Moreover, for each breaking scenario we perform the capability test of DUNE for the determination of $ θ_{23} $ and to establish the phenomenon of CP violation considering the true benchmark point arising from the breaking of $ μ-τ$ reflection symmetry. We also make remarks on the potential of DUNE to rule out maximal CP-violation or CP-conservation hypothesis at a certain confidence level for different scenarios.

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arXiv2018

Non-Standard Neutrino Interactions in a Modified $ν$2HDM

In the traditional neutrinophilic two-Higgs doublet model ($ν$2HDM), there is no non-standard neutrino interaction (NSI) as the interactions between the Standard Model fermions with neutrinos are negligibly small due to the tiny mixing of the two scalar doublets. In this work, we propose that if $ν$2HDM is modified by considering the right-handed electron, $e_R$ is negatively charged under a global $U(1)$-symmetry then one can generate significant amount of NSI along with the tiny Dirac neutrino mass. Depending on different constraints from the LEP experiment, tree level lepton flavor violating processes, big-bang neucleosynthesis etc., we observe that this model significantly restricts the range of permissible NSI parameters, putting a strict upper bound on different NSIs. Furthermore, considering these model-dependent NSIs, we study their impact on the next-generation superbeam experiment, DUNE. We present a detailed discussion on the mass hierarchy sensitivity and the CP-violation discovery study considering the impact of both diagonal as well as off-diagonal NSIs.

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arXiv2018

Neutrinophilic Axion-Like Dark Matter

The axion-like particles (ALPs) are very good candidates of the cosmological dark matter, which can exist in many extensions of the standard model (SM). The mass range of the ALPs as the dark matter can extend from a sub-eV scale to almost $10^{-22}~{\rm eV}$. On the other hand, the neutrinos are found to be massive and the SM must be extended to explain the sub-eV neutrino masses. It becomes very interesting to consider an exclusive coupling between these two low scale frontiers that are both beyond the SM. The propagation of neutrinos inside the Milky Way would undergo the coherent forward scattering effect with the ALP background, and the neutrino oscillation behavior can be modified by the ALP-induced potential. Assuming a derivative coupling between the ALP and the three generations of active neutrinos, possible impacts on the neutrino oscillation experiments have been explored in this paper. In particular, we have numerically studied the sensitivity of the Deep Underground Neutrino Experiment (DUNE). The astrophysical consequences of such coupling have also been investigated systematically.

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arXiv2018

$ μ-τ$ Reflection Symmetry Embedded in Minimal Seesaw

We embed $μ-τ$ reflection symmetry into the minimal seesaw formalism, where two right-handed neutrinos are added to the Standard Model of particle physics. Assuming that both the left- and right-handed neutrino fields transform under $μ-τ$ reflection symmetry, we obtain the required forms of the neutrino Dirac mass matrix and the Majorana mass matrix for the right-handed neutrinos. To investigate the neutrino phenomenology at low energies, we first consider the breaking of $μ-τ$ reflection symmetry due to the renormalization group running, and then systematically study various breaking schemes by introducing explicit breaking terms at high energies.

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arXiv2017

Challenges posed by non-standard neutrino interactions in the determination of $δ_{CP}$ at DUNE

One of the primary objectives of Deep Underground Neutrino Experiment (DUNE) is to discover the leptonic CP violation and to identify it's source. In this context, we study the impact of non-standard neutrino interactions (NSIs) on observing the CP violation signal at DUNE. We explore the impact of various parameter degeneracies introduced by non-zero NSI and identify which of these can influence the CP violation sensitivity and CP precision of DUNE, by considering NSI both in data and in theory. In particular, we study how the CP sensitivity of DUNE is affected because of the intrinsic hierarchy degeneracy which occurs when the diagonal NSI parameter $ε_{ee}=-1$ and $δ_{CP}= \pm 90^{\circ}$.

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