arXiv subjects

Anuj Kumar Upadhyay

Publications and source records attributed to Anuj Kumar Upadhyay.

9 recordsLinked to original sources

arXiv2026

Deep Earth imaging through neutrino and seismic tomography

This article is a report on the Deep Earth Neutrino + Seismic Imaging and TomographY (DENSITY 2026) mini-workshop, held on 23--24 February 2026 in the Department of Earth and Climate Science at the Indian Institute of Science Education and Research (IISER), Pune. The workshop was jointly organised by IISER Pune and the Institute of Physics (IOP), Bhubaneswar. Researchers from Earth Sciences and Neutrino Physics participated in the workshop to explore multipronged approaches for studying the deep interior of the Earth. Since the participants came from diverse scientific disciplines (seismology, geochemistry, mineral physics, and neutrino physics), the programme featured a series of overview talks introducing all participants to the basic concepts of each field and highlighting how these concepts may be applied to the study of the deep Earth.

hep-ex↗

arXiv2026

Constraining the core radius and density jumps inside Earth using atmospheric neutrino oscillations

Atmospheric neutrinos probe the interior of Earth using weak interactions, and provide information complementary to that of gravitational and seismic measurements. While passing through Earth, multi-GeV neutrinos encounter matter effects due to the coherent forward scattering with ambient electrons, which alter the neutrino oscillation probabilities. These matter effects depend upon the density distribution of electrons inside Earth, and hence, can be used to determine the internal structure of Earth. In this work, we employ a five-layered model of Earth where the layer densities and radii are modified, keeping the mass and moment of inertia of Earth unchanged and respecting the hydrostatic equilibrium condition. We use the proposed INO-ICAL detector as an example of an atmospheric neutrino experiment that can distinguish between neutrinos and antineutrinos efficiently in the multi-GeV energy range. Our analyses demonstrate that such an experiment can simultaneously constrain density jumps inside Earth and locate the core-mantle boundary. The charge identification (CID) capability of the ICAL detector would play a crucial role in obtaining these correlated constraints. An ICAL-like detector without CID capability would also be able to perform this task, albeit with a reduced sensitivity.

hep-ph↗

arXiv2026

Establishing Earth's Matter Effect in Atmospheric Neutrino Oscillations at IceCube DeepCore

The discovery of the non-zero value of $θ_{13}$ has opened an exciting opportunity to probe the Earth's matter effects in three-flavor oscillations of atmospheric neutrinos. These matter effects depend on both neutrino energy and the electron density distributions encountered during their propagation through Earth. In this contribution, we present preliminary sensitivities from the DeepCore detector, a densely instrumented sub-array of the IceCube neutrino observatory at the South Pole, demonstrating its ability to observe these matter effects in atmospheric neutrino oscillations. Using simulated data equivalent to 9.3 years of observations at IceCube DeepCore, we show the sensitivity of the DeepCore to reject the vacuum oscillation hypothesis and align with the Preliminary Reference Earth Model. Additionally, we present the expected improvement in sensitivity for rejecting the vacuum oscillations using the upcoming IceCube Upgrade, a low-energy extension of the IceCube detector.

hep-ph↗

arXiv2025

Demonstrating the ability of IceCube DeepCore to probe Earth's interior with atmospheric neutrino oscillations

The IceCube Neutrino Observatory is an optical Cherenkov detector instrumenting one cubic kilometer of ice at the South Pole. The Cherenkov photons emitted following a neutrino interaction are detected by digital optical modules deployed along vertical strings within the ice. The densely instrumented bottom central region of the IceCube detector, known as DeepCore, is optimized to detect GeV-scale atmospheric neutrinos. As upward-going atmospheric neutrinos pass through Earth, matter effects alter their oscillation probabilities due to coherent forward scattering with ambient electrons. These matter effects depend upon the energy of neutrinos and the density distribution of electrons they encounter during their propagation. Using simulated data at the IceCube Deepcore equivalent to its 9.3 years of observation, we demonstrate that atmospheric neutrinos can be used to probe the broad features of the Preliminary Reference Earth Model. In this contribution, we present the preliminary sensitivities for establishing the Earth matter effects, validating the non-homogeneous distribution of Earth's electron density, and measuring the mass of Earth. Further, we also show the DeepCore sensitivity to perform the correlated density measurement of different layers incorporating constraints on Earth's mass and moment of inertia.

hep-ph↗

arXiv2025

Probing Earth's core using atmospheric neutrino oscillations in the presence of NSI at INO-ICAL

Neutrinos can serve as a complementary and independent tool to gravitational and seismic studies in exploring the interior of Earth, thanks to their unique properties: extremely low interaction cross sections and flavor oscillations. With the precise measurements of neutrino oscillation parameters and observation of the non-zero value of mixing angle $θ_{13}$, it has become feasible to detect the forward scattering of GeV-energy atmospheric neutrinos passing through Earth with ambient electrons in the form of matter effects on neutrino oscillation probabilities. These matter effects depend on both the neutrino energy and electron density distribution along their path, making them ideally suited for exploring the inner structure of Earth. Furthermore, in the presence of non-standard interactions (NSI) of neutrinos with matter, oscillation patterns undergo additional modifications. In this study, we quantify the capability of an atmospheric neutrino experiment, such as a magnetized iron calorimeter detector, to validate the Earth's core and measure the position of the core-mantle boundary in the presence of NSI. We perform this study considering a three-layered density profile of Earth. Our analysis demonstrates that neutrino non-standard interactions impact these Earth tomography measurements in comparison to standard interactions.

hep-ph↗

arXiv2025

Exploring constraints on the core radius and density jumps inside Earth using atmospheric neutrino oscillations

Atmospheric neutrinos, through their weak interactions, can serve as an independent tool for exploring the internal structure of Earth. The information obtained would be complementary to that provided by seismic and gravitational measurements. The Earth matter effects in neutrino oscillations depend upon the energy of neutrinos and the electron density distribution that they encounter during their journey through Earth, and hence, can be used to probe the inner structure of Earth. In this contribution, we demonstrate how well an atmospheric neutrino experiment, such as an iron calorimeter detector (ICAL), would simultaneously constrain the density jumps inside Earth and determine the location of the core-mantle boundary. In this work, we employ a five-layered density model of Earth, where the layer densities and core radius are modified to explore the parameter space, ensuring that the mass and moment of inertia of Earth remain constant while satisfying the hydrostatic equilibrium condition. We further demonstrate that the charge identification capability of an ICAL-like detector would play a crucial role in obtaining these correlated constraints.

hep-ph↗

arXiv2024

Probing the interior of Earth using oscillating neutrinos at INO-ICAL

Atmospheric neutrinos offer the possibility of exploring the internal structure of Earth. This information is complementary to the traditional probes of seismic and gravitational studies. While propagating through Earth, the multi-GeV neutrinos encounter the Earth's matter effects due to the coherent forward scattering with the ambient electrons, which alters the neutrino oscillation probabilities. We present how well an atmospheric neutrino oscillation experiment like the 50 kt Iron Calorimeter (ICAL) detector at India-based Neutrino Observatory would validate the presence of Earth's core, measure the location of the core-mantle boundary (CMB), and probe the dark matter (DM) inside the Earth in a unique way through Earth matter effects in neutrino oscillations. Owing to good angular resolution, ICAL can observe the core-passing neutrinos efficiently. Due to its magnetized setup, it would be able to observe neutrinos and antineutrinos separately. With 500 kt$\cdot$yr exposure, the presence of Earth's core can be independently confirmed at ICAL with a median $Δχ^2$ of 7.45 (4.83) for normal (inverted) mass ordering. With 1000 kt$\cdot$yr exposure, ICAL would be able to locate the CMB with a precision of about $\pm$ 250 km at $1σ$. It would also be sensitive to the possible presence of dark matter with 3.5% of the mass of Earth at $1σ$. The charge identification capability of ICAL would play an important role in achieving these precisions.

hep-ph↗

arXiv2023

Probing dark matter inside Earth using atmospheric neutrino oscillations at INO-ICAL

The interior of Earth's core can be explored using weak interactions of atmospheric neutrinos. This would complement gravitational and seismic measurements, paving the way for multimessenger tomography of Earth. Oscillations of atmospheric neutrinos passing through Earth are affected by the ambient electron density. We demonstrate that atmospheric neutrinos can probe the possible existence of dark matter inside Earth's core in a unique way - by measuring the amount of baryonic matter using neutrino oscillations. We find that a detector like ICAL at INO with muon charge identification capability can be sensitive to dark matter with $\sim5\%-6\%$ mass of Earth, at 1$σ$ level with 500 kt$\cdot$yr exposure. We show that while it will not be possible to identify the dark matter profile using neutrino oscillation experiments, the baryonic matter profile inside the core can be probed with atmospheric neutrinos.

hep-ph↗

arXiv2023

Locating the Core-Mantle Boundary using Oscillations of Atmospheric Neutrinos

Atmospheric neutrinos provide a unique avenue to explore the internal structure of Earth based on weak interactions, which is complementary to seismic studies and gravitational measurements. In this work, we demonstrate that the atmospheric neutrino oscillations in the presence of Earth matter can serve as an important tool to locate the core-mantle boundary (CMB). An atmospheric neutrino detector like the proposed 50 kt magnetized ICAL at INO can observe the core-passing neutrinos efficiently. These neutrinos would have experienced the MSW resonance and the parametric or neutrino oscillation length resonance. The net effect of these resonances on neutrino flavor conversions depends upon the location of CMB and the density jump at that radius. We quantify the capability of ICAL to measure the location of CMB in the context of multiple three-layered models of Earth. For the model where the density and the radius of core are kept flexible while the mass and radius of Earth as well as the densities of outer and inner mantle are fixed, ICAL can determine the location of CMB with a 1$σ$ precision of about 250 km with an exposure of 1000 kt$\cdot$yr. With the 81-layered PREM profile, this $1σ$ precision would be about 350 km. The charge identification capability of ICAL plays an important role in achieving this precision.

hep-ph↗