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Kalpana Bora

Publications and source records attributed to Kalpana Bora.

29 records · Page 2Linked to original sources
arXiv2016

Octant Degeneracy, Quadrant of CPV phase at Long Baseline $ν$ Experiments and Baryogenesis

In a recent work by two of us, we have studied, how CP violation discovery potential can be improved at long baseline neutrino experiments (LBNE/DUNE), by combining with its ND (near detector) and reactor experiments. In this work, we discuss how this study can be further analyzed to resolve entanglement of the quadrant of leptonic CPV phase and Octant of atmospheric mixing angle $θ_{23}$, at LBNEs. The study is done for both NH (Normal hierarchy) and IH (Inverted hierarchy), HO (Higher Octant) and LO (Lower Octant). We show how leptogenesis can enhance the effect of resolving this entanglement, and how possible values of the leptonic CPV phase can be predicted in this context. Carrying out numerical analysis based on the recent updated experimental results for neutrino mixing angles, we predict the values of the leptonic CPV phase for 152 possible cases. We also confront our predictions of the leptonic CPV phase with the updated global fit and find that five values of $δ_{CP}$ are favoured by BAU constraints. One of the five values matches with the recent global fit value of $δ_{CP}$ (leptonic CPV phase) close to 1.41 $π$ in our model independent scenario. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework in a model independent way.

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arXiv2015

Charged Lepton Flavor Violation $μ\rightarrow eγ$ in $μ-τ$ Symmetric SUSY SO(10) mSUGRA, NUHM, NUGM, and NUSM theories and LHC

Charged Lepton Flavor Violation (cLFV) processes like $ μ\rightarrow e γ$ are rare decay processes, that are another signature of physics beyond Standard Model (BSM). These processes have been studied in various models, that could explain neutrino oscillations and mixings. In this work, we present bounds on cLFV decay $ μ\rightarrow e γ$ in a $ μ$-$ τ$ symmetric SUSY SO(10) theory, using type I seesaw mechanism. The updated constraints on BR($ μ\rightarrow e γ$) from MEG experiment, recently measured value of Higgs mass at LHC and value of $θ_{13}$ from reactor data have been used. We present our results in mSUGRA, NUHM, NUGM and NUSM models, and sensitivity to test these theories at next run of LHC is also discussed.

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arXiv2015

Neutrino-Nucleon Cross section in Ultra High Energy Regime

Neutrino Physics is now entering precision era and neutrino-nucleon cross sections are an im- portant ingredient in all neutrino oscillation experiments. Specially, precise knowledge of neutrino- nucleon cross sections in Ultra High Energy (UHE) regime (TeV-PeV) is becoming more important now, as several experiments worldwide are going to observe processes involving such UHE neutrinos. In this work, we present new results on neutrino-nucleon cross-sections in this UHE regime, using QCD.

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arXiv2015

Determining the Octant of $θ_{23}$ at LBNE in conjunction with Reactor Experiments

We have explored the possibilities of resolving the $θ_{23}$ octant degeneracy present in the newly planned Long-Baseline Neutrino Experiment (LBNE) by combining reactor data. Reactor experiments have already measured the third mixing angle $θ_{13}$ very precisely and this precise measurenent of $θ_{13}$ in turn helps in $θ_{23}$ octant measurement. We have examined the octant sensitivity with and without reactor data and it improves if reactor data is added. The comparative study of octant sensitivities of 10kt and 35kt liquid argon Far Detectors, with and without the Near Detector, reveals that the sensitivity increases with an increase in detector mass. Also, the presence of the Near Detector improves the sensitivity. The effect of adding priors on octant determination is also studied in this work.

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arXiv2015

Resolving Octant Degeneracy at LBL experiment by combining Daya Bay Reactor Setup

Long baseline Experiment (LBL) have promised to be a very powerful experimental set up to study various issues related to Neutrinos. Some ongoing and planned LBL and medium baseline experiments are - T2K, MINOS, NOvA, LBNE, LBNO etc. But the long baseline experiments are crippled due to presence of some parameter degeneracies, like the Octant degeneracy. In this work, we first show the presence of Octant degeneracy in LBL experiments, and then combine it with Daya Bay Reactor experiment, at different values of CP violation phase. We show that the Octant degeneracy in LBNE can be resolved completely with this proposal.

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arXiv2014

Probing CP violation at LBNE with reactor experiments

In this work, we have explored the possibilities of improving CP violation discovery potential of newly planned Long-Baseline Neutrino Experiment (LBNE), U.S.A., by combining with data from reactors. The third mixing angle $θ_{13}$ is now very precisely measured and this precise measurenent of $θ_{13}$ helps in measurement of CP violation. Here, CP violation is studied with and without data from reactors. Impact of placing a ND is also studied. It is found that CPV discovery potential of LBNE with ND increases when combined with data from reactors. With a far detector of 35 kt, it is possible to obtain 5$σ$ sensitivity of CPV when run for 5 years in $ν$ and 5 years in $\barν$ mode. When hierarchy is assumed to be normal hierarchy, CPV sensitivity is maximum. CPV discovery is possible by combining 5 years neutino data from LBNE with 3 years anti-neutrino from reactors. This study reveals that CPV can also be discovered at 5$σ$ cl in IH mode when appearance measurement of LBNE is combined with reactors.

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arXiv2012

Probing Sterile Neutrino Parameters with Double Chooz, Daya Bay and RENO

In this work, we present a realistic analysis of the potential of the present-day reactor experiments Double Chooz, Daya Bay and RENO for probing the existence of sterile neutrinos. We present exclusion regions for sterile oscillation parameters for each of these experiments, using simulations with realistic estimates of systematic errors and detector resolutions, and compare the sterile parameter sensitivity regions we obtain with the existing bounds from other reactor experiments. We find that these experimental set-ups give significant bounds on the parameter Θ_{ee} especially in the low sterile oscillation region 0.01 < Δm_{41}^2 < 0.05 eV^2. These bounds can add to our understanding of the sterile neutrino sector since there is still a tension in the allowed regions from different experiments for sterile parameters.

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arXiv2011

Parameter degeneracies in FNAL-Homestake LBNE setup

LBNE (Longbaseline Neutrino Oscillation Experiments) provide a powerful experimental setup to study sensitivities and exlcusion limits in neutrino oscillation parameter space. A longbaseline experiment is being planned, at USA, from FNAL (Fermilab National Accelerator Laboratory) to an underground laboratory at Homestake in South Dakota, at an angle of 5.84 degrees from FNAL (at a distance of 1289 km). The prospect of a new beamline towards this location from FNAL, and a 300 Kiloton water Cerenkov detector at the site is in planning stage, for the studies of the neutrino physics program. The long baseline provides sufficient matter effects for neutrino travel, and a large detrecor will help towards better statistics. In this work, we present, upto what extent, the parameter degeneracies, present in oscillation parameter space, can be resolved, using this FNAL-LBNE setup.

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arXiv2011

Flavor unification, dark matter, proton decay and other observable predictions with low-scale $S_4$ symmetry

We show how gauge coupling unification is successfully implemented through non-supersymmetric grand unified theory, $SO(10)\times G_f (~G_f=S_4, SO(3)_f, SU(3)_f)$, using low-scale flavor symmetric model of the type $SU(2)_L\times U(1)_Y$ $ \times SU(3)_C \times S_4$ recently proposed by Hagedorn, Lindner, and Mohapatra, while assigning matter-parity discrete symmetry for the dark matter stability. For gauge coupling unification in the single-step breaking case, we show that a color-octet fermion and a hyperchargeless weak-triplet fermionic dark matter are the missing particles needed to complete its MSSM-equivalent degrees of freedom. When these are included the model automatically predicts the nonsupersymmetric grand unification with a scale identical to the minimal supersymmetric standard model/grand unified theory scale. We also find a two-step breaking model with Pati-Salam intermediate symmetry where the dark matter and a low-mass color-octet scalar or the fermion are signaled by grand unification. The proton-lifetime predictions are found to be accessible to ongoing or planned searches in a number of models. We discuss grand unified origin of the light fermionic triplet dark matter, the color-octet fermion, and their phenomenology.

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arXiv2007

$ν$ masses in a SUSY SO(10) theory with spontaneous CP violation

We propose a possibility of spontaneous CP-violation (SCPV) at high scale in a SUSY SO(10) theory. The model is L-R symmetric SUSY SO(10) with \textbf{\noun{10}} and \textbf{126} dimensional Higgs generating fermion masses, and the CP phase is generated through complex VEV of B-L breaking \textbf{126} Higgs . The model can have potential application in explaining $ν$ masses and leptogenesis as well.

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