arXiv subjects

Tarak Thakore

Publications and source records attributed to Tarak Thakore.

10 recordsLinked to original sources

arXiv2019

Enhancing Sensitivity to Non-Standard Neutrino Interactions at INO combining muon and hadron information

The neutral current non-standard interactions (NSI's) of neutrino with matter fermions while propagating through long distances inside the Earth matter can give rise to the extra matter potentials apart from the standard MSW potential due to the $W$-mediated interactions in matter. In this paper, we explore the impact of flavor violating neutral current NSI parameter $\varepsilon_{μτ}$ in the oscillation of atmospheric neutrino and antineutrino using the 50 kt magnetized ICAL detector at INO. We find that due to non-zero $\varepsilon_{μτ}$, $ν_μ\rightarrowν_μ$ and $\barν_μ\rightarrow\barν_μ$ transition probabilities get modified substantially at higher energies and longer baselines, where vacuum oscillation dominates. We estimate the sensitivity of the ICAL detector for various choices of binning schemes and observables. The most optimistic bound on $\varepsilon_{μτ}$ that we obtain is $-0.01 < \varepsilon_{μτ} < 0.01 $ at 90$\%$ C.L. using 500 kt$\cdot$yr exposure and considering $E_μ,\, \cosθ_μ,\,E'_{\rm had}$ as observables in their ranges [1, 21] GeV, [-1, 1], and [0, 25] GeV respectively. For the first time we show that the charge identification capability of the ICAL detector is crucial to set stringent constraints on $\varepsilon_{μτ}$. We also show that when we marginalize over $\varepsilon_{μτ}$ in fit in its range of -0.1 to 0.1, the mass hierarchy sensitivity deteriorates by 10$\%$ to 20$\%$ depending on the analysis mode, and the precision measurements of atmospheric parameters remain quite robust at the ICAL detector.

hep-ph↗

arXiv2019

Enhancing the hierarchy and octant sensitivity of ESS$ν$SB in conjunction with T2K, NO$ν$A and ICAL@INO

The main aim of the ESS$ν$SB proposal is the discovery of the leptonic CP phase $δ_{CP}$ with a high significance ($5σ$ for 50% values of $δ_{CP}$) by utilizing the physics at the second oscillation maxima of the $P_{μe}$ channel. It can achieve $3σ$ sensitivity to hierarchy for all values of $δ_{CP}$. In this work, we concentrate on the hierarchy and octant sensitivity of the ESS$ν$SB experiment. We show that combining the ESS$ν$SB experiment with the atmospheric neutrino data from the proposed India-based Neutrino Observatory(INO) experiment can result in an increased sensitivity to mass hierarchy. In addition, we also combine the results from the ongoing experiments T2K and NO$ν$A assuming their full runtime and present the combined sensitivity of ESS$ν$SB + ICAL@INO + T2K + NO$ν$A. We show that while by itself ESS$ν$SB can have up to $3σ$ hierarchy sensitivity, the combination of all the experiments can give up to $5σ$ sensitivity depending on the true hierarchy-octant combination. The octant sensitivity of ESS$ν$SB is low by itself. However the combined sensitivity of all the above experiments can give up to $3σ$ sensitivity depending on the choice of true hierarchy and octant. We discuss the various degeneracies and the synergies that lead to the enhanced sensitivity when combining different experimental data.

hep-ph↗

arXiv2018

Active-sterile neutrino oscillations at INO-ICAL over a wide mass-squared range

We perform a detailed analysis for the prospects of detecting active-sterile oscillations involving a light sterile neutrino, over a large $Δm^2_{41}$ range of $10^{-5}$ eV$^2$ to $10^2$ eV$^2$, using 10 years of atmospheric neutrino data expected from the proposed 50 kt magnetized ICAL detector at the INO. This detector can observe the atmospheric $ν_μ$ and $\barν_μ$ separately over a wide range of energies and baselines, making it sensitive to the magnitude and sign of $Δm^2_{41}$ over a large range. If there is no light sterile neutrino, ICAL can place competitive upper limit on $|U_{μ4}|^2 \lesssim 0.02$ at 90\% C.L. for $Δm^2_{41}$ in the range $(0.5 - 5) \times 10^{-3}$ eV$^2$. For the same $|Δm^2_{41}|$ range, ICAL would be able to determine its sign, exploiting the Earth's matter effect in $μ^{-}$ and $μ^{+}$ events separately if there is indeed a light sterile neutrino in Nature. This would help identify the neutrino mass ordering in the four-neutrino mixing scenario.

hep-ph↗

arXiv2018

Can INO be Sensitive to Flavor-Dependent Long-Range Forces?

Flavor-dependent long-range leptonic forces mediated by the ultra-light and neutral bosons associated with gauged $L_e-L_μ$ or $L_e-L_τ$ symmetry constitute a minimal extension of the Standard Model. In presence of these new anomaly free abelian symmetries, the SM remains invariant and renormalizable, and can lead to interesting phenomenological consequences. For an example, the electrons inside the Sun can generate a flavor-dependent long-range potential at the Earth surface, which can enhance $ν_μ$ and $\barν_μ$ survival probabilities over a wide range of energies and baselines in atmospheric neutrino experiments. In this paper, we explore in detail the possible impacts of these long-range flavor-diagonal neutral current interactions due to $L_e-L_μ$ and $L_e-L_τ$ symmetries (one at-a-time) in the context of proposed 50 kt magnetized ICAL detector at INO. Combining the information on muon momentum and hadron energy on an event-by-event basis, ICAL can place stringent constraints on the effective gauge coupling $α_{eμ/eτ}<1.2\times 10^{-53}$ ($1.75\times 10^{-53}$) at 90$\%$ (3$σ$) C.L. with 500 kt$\cdot$yr exposure. The 90$\%$ C.L. limit on $α_{eμ}$ ($α_{eτ}$) from ICAL is $\sim 46$ (53) times better than the existing bound from the Super-Kamiokande experiment.

hep-ph↗

arXiv2017

Sensitivity to neutrino decay with atmospheric neutrinos at INO

Sensitivity of the magnetised Iron CALorimeter (ICAL) detector at the proposed India-based Neutrino Observatory (INO) to invisible decay of the mass eigenstate $ν_3$ using atmospheric neutrinos is explored. A full three-generation analysis including earth matter effects is performed in a framework with both decay and oscillations. The wide energy range and baselines offered by atmospheric neutrinos are shown to be excellent for constraining the $ν_3$ lifetime. We find that with an exposure of 500 kton-yr the ICAL atmospheric experiment could constrain the $ν_3$ lifetime to $τ_3/m_3>1.51\times10^{-10}$ s/eV at the 90\% C.L. This is two orders of magnitude tighter than the bound from MINOS. The effect of invisible decay on the precision measurement of $θ_{23}$ and $|Δ{m^2_{32}}|$ is also studied.

hep-ph↗

arXiv2017

Physics Potential of the ICAL detector at the India-based Neutrino Observatory (INO)

The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.

physics.ins-det↗

arXiv2015

Enhancing sensitivity to neutrino parameters at INO combining muon and hadron information

The proposed ICAL experiment at INO aims to identify the neutrino mass hierarchy from observations of atmospheric neutrinos, and help improve the precision on the atmospheric neutrino mixing parameters. While the design of ICAL is primarily optimized to measure muon momentum, it is also capable of measuring the hadron energy in each event. Although the hadron energy is measured with relatively lower resolution, it nevertheless contains crucial information on the event, which may be extracted when taken concomitant with the muon data. We demonstrate that by adding the hadron energy information to the muon energy and muon direction in each event, the sensitivity of ICAL to the neutrino parameters can be improved significantly. Using the realistic detector response for ICAL, we present its enhanced reach for determining the neutrino mass hierarchy, the atmospheric mass squared difference and the mixing angle theta23, including its octant. In particular, we show that the analysis that uses hadron energy information can distinguish the normal and inverted mass hierarchies with Deltachi^2 approx 9 with 10 years exposure at the 50 kt ICAL, which corresponds to about 40% improvement over the muon-only analysis.

hep-ph↗

arXiv2014

A Simulations Study of the Muon Response of the Iron Calorimeter Detector at the India-based Neutrino Observatory

The magnetised Iron CALorimeter detector (ICAL), proposed to be built at the India-based Neutrino Observatory (INO), is designed to study atmospheric neutrino oscillations. The ICAL detector is optimized to measure the muon momentum, its direction and charge. A GEANT4-based package has been developed by the INO collaboration to simulate the ICAL geometry and propagation of particles through the detector. The simulated muon tracks are reconstructed using the Kalman Filter algorithm. Here we present the first study of the response of the ICAL detector to muons using this simulations package to determine the muon momentum and direction resolutions as well as their reconstruction and charge identification efficiencies. For 1-20 GeV/c muons in the central region of the detector, we obtain an average angle-dependent momentum resolution of 9-14%, an angular resolution of about a degree, reconstruction efficiency of about 80% and a correct charge identification of about 98%.

physics.ins-det↗

arXiv2013

The Reach of INO for Atmospheric Neutrino Oscillation Parameters

The India-based Neutrino Observatory (INO) will host a 50 kt magnetized iron calorimeter (ICAL@INO) for the study of atmospheric neutrinos. Using the detector resolutions and efficiencies obtained by the INO collaboration from a full-detector GEANT4-based simulation, we determine the reach of this experiment for the measurement of the atmospheric neutrino mixing parameters ($\sin^2 θ_{23}$ and $|Δm_{32}^2 |$). We also explore the sensitivity of this experiment to the deviation of $θ_{23}$ from maximal mixing, and its octant.

hep-ph↗

arXiv2013

Determining the Neutrino Mass Hierarchy with INO, T2K, NOvA and Reactor Experiments

The relatively large measured value of $θ_{13}$ has opened up the possibility of determining the neutrino mass hierarchy through earth matter effects. Amongst the current accelerator-based experiments only NOvA has a long enough baseline to observe earth matter effects. However, NOvA is plagued with uncertainty on the knowledge of the true value of $δ_{CP}$, and this could drastically reduce its sensitivity to the neutrino mass hierarchy. The earth matter effect on atmospheric neutrinos on the other hand is almost independent of $δ_{CP}$. The 50 kton magnetized Iron CALorimeter at the India-based Neutrino Observatory (ICAL@INO) will be observing atmospheric neutrinos. The charge identification capability of this detector gives it an edge over others for mass hierarchy determination through observation of earth matter effects. We study in detail the neutrino mass hierarchy sensitivity of the data from this experiment simulated using the Nuance based generator developed for ICAL@INO and folded with the detector resolutions and efficiencies obtained by the INO collaboration from a full Geant4-based detector simulation. The data from ICAL@INO is then combined with simulated data from T2K, NOvA, Double Chooz, RENO and Daya Bay experiments and a combined sensitivity study to the mass hierarchy is performed. With 10 years of ICAL@INO data combined with T2K, NOvA and reactor data, one could get about $2.3σ-5.7σ$ discovery of the neutrino mass hierarchy, depending on the true value of $\sin^2θ_{23}$ [0.4 -- 0.6], $\sin^22θ_{13}$ [0.08 -- 0.12] and $δ_{CP}$ [0 -- 2$π$].

hep-ph↗