arXiv subjects

Ritam Kundu

Publications and source records attributed to Ritam Kundu.

4 recordsLinked to original sources

arXiv2026

Quantum Information as a New Lens for Precision Neutrino Physics

We present a quantum-information-theoretic study of three-flavor neutrino oscillations in long-baseline experiments by mapping flavor states to qubit-like representations and quantifying quantum correlations through total concurrence. The local minima of this entanglement measure identify energy regions where the flavor state is closest to separability, enabling cleaner extraction of oscillation parameters. We explain how these local minima offer opportunities for precision measurements and provide insight into the accurate determination of neutrino oscillation parameters. We then propose a strategy to improve parameter extraction by aligning the benchmark oscillation regions of NO$\nu$A and T2K with the minimum entanglement achievable in each experiment. This shifts the concurrence minima toward higher-event-count energy regions, leading to tighter constraints and reducing the tension arising from their different energy regimes. For normal ordering, we obtain $(0.581^{+0.0136}_{-0.0150},,195^{+38}_{-32},^\circ)$ in the $(\sin^2\theta_{23},\delta_{\rm CP})$ plane and $(0.580^{+0.0140}_{-0.0153},,2.515^{+0.0344}_{-0.0344}\times10^{-3},\mathrm{eV}^2)$ in the $(\sin^2\theta_{23},\Delta m^2_{31})$ plane, yielding improved joint constraints. Using GLoBES simulations together with real data, we assess how local minima of quantum correlations influence leptonic CP-violation sensitivity, $\theta_{23}$ octant-degeneracy resolution, and mass-ordering determination. Our results show that minimizing entanglement can significantly affect these key sensitivities, highlighting quantum information measures as complementary probes of neutrino flavor oscillations and offering new insight into the role of quantum correlations in precision neutrino physics.

hep-ph↗

arXiv2026

Precision measurements of 2-3 oscillation parameters in the next-generation long-baseline experiments

Over the past few decades, data from leading neutrino experiments have firmly established neutrino oscillation, implying non-zero neutrino masses and leptonic mixing and thereby providing confirmed evidence of physics beyond the Standard Model. On the backdrop of the precision era of neutrino oscillation, this thesis underscores its relevance by demonstrating the physics reach of the forthcoming long-baseline experiments -- Deep Underground Neutrino Experiment (DUNE) and Hyper-Kamiokande (Hyper-K) -- to establish non-maximal $\theta_{23}$, resolve the correct $\theta_{23}$ octant, and improve the precision on $\theta_{23}$ and $\Delta m^2_{31}$ by efficiently breaking parameter degeneracies. This is enabled by DUNE's high-resolution LArTPC detector and its wide-band beam, achieving sensitivity at a high confidence level compared to the global fits of world neutrino data. The combined analysis of DUNE and Hyper-K not only significantly enhances sensitivity to these phenomenological studies but also demonstrates their capabilities at lower exposures when operated together, relative to their nominal individual exposures. In addition, we investigate the impact of flavor-dependent long-range interactions arising from anomaly-free U(1)' extensions of the Standard Model, showing that although subdominant long-range interactions can substantially influence the sensitivity and precision of oscillation parameter measurements, the complementary strengths of DUNE and Hyper-K mitigate these challenges to a large extent.

hep-ph↗

arXiv2024

Improved precision on 2-3 oscillation parameters using the synergy between DUNE and T2HK

A high-precision measurement of $\Delta m^2_{31}$ and $\theta_{23}$ is inevitable to estimate the Earth's matter effect in long-baseline experiments which in turn plays an important role in addressing the issue of neutrino mass ordering and to measure the value of CP phase in $3\nu$ framework. After reviewing the results from the past and present experiments, and discussing the near-future sensitivities from the IceCube Upgrade and KM3NeT/ORCA, we study the expected improvements in the precision of 2-3 oscillation parameters that the next-generation long-baseline experiments, DUNE and T2HK, can bring either in isolation or combination. We highlight the relevance of the possible complementarities between these two experiments in obtaining the improved sensitivities in determining the deviation from maximal mixing of $\theta_{23}$, excluding the wrong-octant solution of $\theta_{23}$, and obtaining high precision on 2-3 oscillation parameters, as compared to their individual performances. We observe that for the current best-fit values of the oscillation parameters and assuming normal mass ordering (NMO), DUNE + T2HK can establish the non-maximal $\theta_{23}$ and exclude the wrong octant solution of $\theta_{23}$ at around 7$\sigma$ C.L. with their nominal exposures. We find that DUNE + T2HK can improve the current relative 1$\sigma$ precision on $\sin^{2}\theta_{23}~(\Delta m^{2}_{31})$ by a factor of 7 (5) assuming NMO. Also, we notice that with less than half of their nominal exposures, the combination of DUNE and T2HK can achieve the sensitivities that are expected from these individual experiments using their full exposures. We also portray how the synergy between DUNE and T2HK can provide better constraints on ($\sin^2\theta_{23}$ - $\delta_{\mathrm{CP}}$) plane as compared to their individual reach.

hep-ph↗

arXiv2021

A close look on 2-3 mixing angle with DUNE in light of current neutrino oscillation data

Recent global fit analyses of oscillation data show a preference for normal mass ordering (NMO) at 2.5$σ$ and provide 1.6$σ$ indications for lower $θ_{23}$ octant and leptonic CP violation. A high-precision measurement of $θ_{23}$ is pivotal to convert these hints into discoveries. In this work, we study in detail the capabilities of DUNE to establish the deviation from maximal $θ_{23}$ and to resolve its octant at high confidence levels. We exhibit the possible correlations and degeneracies among $\sin^2θ_{23}$, $Δm^2_{31}$, and $δ_{CP}$ in disappearance and appearance oscillation channels at the probability and event levels. Introducing for the first time, a bi-events plot in the plane of total $ν$ and $\barν$ disappearance events, we discuss the impact of $\sin^2θ_{23}$ - $Δm^2_{31}$ degeneracy in establishing non-maximal $θ_{23}$ and show how this degeneracy can be resolved by exploiting the spectral shape information in $ν$ and $\barν$ disappearance events. A 3$σ$ (5$σ$) determination of non-maximal $θ_{23}$ is possible in DUNE in total 7 years if $\sin^2θ_{23} \lesssim 0.465~(0.450)$ or $\sin^2θ_{23} \gtrsim 0.554~(0.572)$ for any value of $δ_{CP}$ and NMO. We study the individual contributions from appearance and disappearance channels, impact of systematic uncertainties and marginalization over oscillation parameters, importance of spectral analysis and data from both $ν$ and $\barν$ runs, while analyzing DUNE's sensitivity to establish non-maximal $θ_{23}$. DUNE can resolve the octant of $θ_{23}$ at 4.2$σ$ (5$σ$) using 7 (10) years of run assuming $\sin^2θ_{23}$ = 0.455, $δ_{CP}$ = $223^\circ$, and NMO. DUNE can improve the current relative 1$σ$ precision on $\sin^2θ_{23}$ ($Δm^2_{31}$) by a factor of 4.4 (2.8) using 7 years of run.

hep-ph↗