We present the first unified study of Earth matter-density stratification and Planck-scale quantum-gravity effects in long-baseline neutrino oscillations, treating both as correlated systematic uncertainties within a full three-flavor framework. Neutrino propagation is computed using matrix exponentiation with spatially resolved Preliminary Reference Earth Model (PREM) density profiles, allowing a quantitative assessment of matter-profile effects beyond the constant-density approximation. We find that the resulting bias in the reconstructed CP-violating phase remains below 0.3° for baselines (L \lesssim 5000) km, but increases to 17.8° at (L=7000) km and 172.2° at (L=12000) km, leading to a potential sign reversal of the inferred CP violation. We further incorporate Planck-scale corrections through the unique gauge-invariant dimension-5 operator of the Standard Model effective field theory. For quasi-degenerate neutrino masses ((m \sim 2) eV), the solar mass-squared splitting receives a correction of order ((1.0 \pm 0.5)\times10^{-5},\mathrm{eV}^2), while the atmospheric splitting remains essentially unchanged. Most importantly, we identify a previously unexplored degeneracy regime in which Planck-scale perturbations can partially compensate matter-induced biases. Around (L\approx7000) km, specific Majorana phases reduce the combined bias by about 30%, demonstrating that the two effects cannot be treated independently. These results highlight the necessity of propagating both Earth-density and quantum-gravity uncertainties as correlated systematics in precision measurements of leptonic CP violation.
Flavour oscillations of sub-GeV atmospheric neutrinos and antineutrinos, traversing different distances inside the Earth, are a promising source of information on the leptonic CP phase $δ$. In that energy range, the oscillations are very fast, far beyond the resolution of modern neutrino detectors. However, the necessary averaging over the experimentally typical energy and azimuthal angle bins does not wash out the CP violation effects. In this paper we derive very accurate analytic compact expressions for the averaged oscillations probabilities. Assuming spherically symmetric Earth, the avera…
We find an analytical expression of neutrino evolution operator in the Earth matter using perturbative approach in the context of three neutrino oscillations. We find that our analytical expression is highly accurate by comparing its results with the numerical solutions of neutrino evolution equation at energy scales relevant for solar, reactor, atmospheric, and accelerator neutrinos. Using our analytical approach we study the accuracy of hypothesis of treating the Earth density piecewise constant. We also study how the Earth matter effect can change the sensitivity to CP phase parameter $δ_{C…
We study in details the Earth matter effects on the boron neutrinos from the Sun using recently developed 3D models of the Earth. The models have a number of new features of the density profiles, in particular, a substantial deviation from spherical symmetry. In this connection, we further elaborate on relevant aspects of oscillations ($ε^2$ corrections, adiabaticity violation, entanglement, {\it etc.}) and the attenuation effect. The night excesses of the $νe-$ and $νN-$ events and the Day-Night asymmetries, $A_{ND}$, are presented in terms of the matter potential and the generalized energy r…
Neutrinos have two properties that make them fairly unique from other known particles: extremely low cross sections and flavor changing oscillations. With a good knowledge of the oscillation parameters soon in hand, it will become possible to detect low-energy atmospheric neutrinos sensitive to the forward elastic scattering off electrons in the Earth's core providing a measurement of the core properties and the matter effect itself. As the dynamics of the Earth's core are complicated and in a difficult to probe environment, additional information from upcoming neutrino experiments will provid…
Modern proposed atmospheric neutrino oscillation experiments, such as PINGU in the Antarctic ice or ORCA in Mediterranean sea water, aim for precision measurements of the oscillation parameters including the ordering of the neutrino masses. They can, however, go far beyond that: Since neutrino oscillations are affected by the coherent forward scattering with matter, neutrinos can provide a new view on the interior of the earth. We show that the proposed atmospheric oscillation experiments can measure the lower mantle density of the earth with a precision at the level of a few percent, includin…
We explore in detail oscillations of the solar $^7$Be neutrinos in the matter of the Earth. The depth of oscillations is about $(0.1 - 0.2)\%$ and the length $\approx 30$ km. The period of the oscillatory modulations in the energy scale is comparable with the width of the line determined by the temperature in the center of the Sun. The latter means that depending on the length of trajectory (nadir angle) one obtains different degree of averaging of oscillations. Exploring these oscillations it is possible to measure the width of the $^7$Be line and therefore the temperature of the Sun, determi…
The experimental observation of neutron - antineutron oscillations is one of the oldest problems of elementary-particle physics. However, the search for these processes in the laboratories on the Earth have thus far yielded no results. In this paper, we consider the possibility of finding $n - \tilde n$ oscillations in the solar cosmic rays at flare increases. There are two arguments in favour of such an approach to this problem: a long distance for a neutron run and a weak magnetic field in the solar cosmic-ray environment. Therefore, the presence of antinucleons in solar cosmic rays may be a…
We advocate the extraterrestrial solar neutrino physics (etSNP) as a means of investigating solar neutrino physics (SNP). As we already know, the dominant and subdominant (vacuum) oscillation lengths would be approximately one kilometer and one hundred kilometers. On the other hand, we know so far that the matter-enhanced oscillations take place only in the core of the Sun. Thus, the etSNP, i.e. solar neutrino physics that could be extracted outside the Earth, would assume a special unique role. The etSNP experiments include (1) a satellite (detector) around the Earth or around the Jupiter or …
The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth's inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth's electron density. The Earth's chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth's ma…
In this paper, we study the effect of conversion of super-light sterile neutrino (SLSN) to electron neutrino in matter like that of the Earth. In the Sun the resonance conversion between SLSN and electron neutrino via the neutral current is suppressed due to the smallness of neutron number. On the other hand, neutron number density can play an important role in the Earth, making the scenario of SLSN quite interesting. The effect of CP-violating phases on active-SLSN oscillations is also discussed. Reactor neutrino experiments with medium or short baseline may probe the scenario of SLSN.
We elucidate the mechanism of enhancement of the $\barν_μ \to \barν_{s}$ transitions at small mixing angles of Earth-core-crossing neutrinos, which is at the basis of the recent result of the IceCube experiment on atmospheric muon anti-neutrino oscillations into sterile anti-neutrino.
In a recent combined analysis of short baseline neutrino oscillation data by Conrad et al it is shown that (3+3) neutrino model, defined by three active and three sterile neutrinos, results in an overall goodness of $67\%$ and a compatibility of $90\%$ among all data sets - to be compared to the compatibility of $0.043\% $ and $13\% $ for a (3+1) and a (3+2) model, respectively. Aside from the fact that (3+3) model still finds inconsistencies with MiniBooNE appearance data sets, its high quality overall compatibility and goodness of fit led us to study the atmospheric neutrinos in this model w…
KM3NeT-ORCA is a water-Cherenkov neutrino detector designed for studying the oscillations of atmospheric neutrinos, with the primary objective of measuring the neutrino mass ordering. Atmospheric neutrinos crossing the Earth undergo matter effects, modifying the pattern of their flavour oscillations. The study of the angular and energy distribution of neutrino events in ORCA can therefore provide tomographic information on the Earth's interior with an independent technique, complementary to the standard geophysics methods. Preliminary estimations based on a full Monte Carlo simulation of the d…
NuCraft (nucraft.hepforge.org) is an open-source Python project that calculates neutrino oscillation probabilities for neutrinos from cosmic-ray interactions in the atmosphere for their propagation through Earth. The solution is obtained by numerically solving the Schrödinger equation. The code supports arbitrary numbers of neutrino flavors including additional sterile neutrinos, CP violation, arbitrary mass hierarchies, matter effects with a configurable Earth model, and takes into account the production height distribution of neutrinos in the Earth's atmosphere.
Studies on Response Uniformity of RPC and Exploring Oscillation Dip and Valley, Non-Standard Interactions, and Earth's Core using Atmospheric Neutrinos at ICAL-INO detector
We study the earth matter effects in the Tokai-to-Kamioka-and-Korea experiment (T2KK), which is a proposed extension of the T2K (Tokai-to-Kamioka) neutrino oscillation experiment between J-PARC at Tokai and Super-Kamiokande (SK) in Kamioka, where an additional detector is placed in Korea along the same neutrino beam line.By using recent geophysical measurements, we examine the earth matter effects on the oscillation probabilities at Kamioka and Korea. The average matter density along the Tokai-to-Kamioka baseline is found to be 2.6 g/cm^3, and that for the Tokai-to-Korea baseline is 2.85, 2.98…
