Matter-Induced CPT Violation and Earth-Density Stratification Effects in Long-Baseline Neutrino Oscillation Experiments
Abstract
We present a unified analysis of two matter-potential systematics in long-baseline (LBL) neutrino oscillation experiments. Matter-induced extrinsic CPT violation produces a non-zero asymmetry AμeCPT = (Pμe − Pμ̅e̅)/(Pμe + Pμ̅e̅), computed here with exact three-flavour matrix-exponentiation propagators for T2K, NOνA, DUNE, and Hyper-Kamiokande; values range from 0.022 to 0.180 at the respective peak energies and differ by up to 9\% between normal and inverted mass orderings. The three-dimensional surface AμeCPT(E, δCP) at the DUNE baseline reveals an entanglement between extrinsic CPT violation and intrinsic CP violation in the high-L/E regime that requires joint statistical treatment. Concurrently, replacing the Preliminary Reference Earth Model (PREM) with a constant path-averaged density introduces a δCP-reconstruction bias below 0.3∘ for L ≤ 5000 km but growing to 17.8∘ at L = 7000 km and 172.2∘ at L = 12000 km. Since both effects share the same matter-potential Hamiltonian they must be modelled jointly; a Poisson log-likelihood χ2 statistic with nuisance-parameter pull terms is used to quantify the bias.
Related
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BibTeX
@misc{pandit2026matterinduced,
title = {{Matter-Induced CPT Violation and Earth-Density Stratification Effects in Long-Baseline Neutrino Oscillation Experiments}},
author = {Tia Pandit and Bipin Singh Koranga and Aditya Pant and Vivek Kumar Nautiyal},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.00436},
eprint = {2608.00436},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.00436},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Matter-Induced CPT Violation and Earth-Density Stratification Effects in Long-Baseline Neutrino Oscillation Experiments
AU - Tia Pandit
AU - Bipin Singh Koranga
AU - Aditya Pant
AU - Vivek Kumar Nautiyal
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2608.00436
UR - https://arxiv.org/abs/2608.00436
AB - We present a unified analysis of two matter-potential systematics in long-baseline (LBL) neutrino oscillation experiments. Matter-induced extrinsic CPT violation produces a non-zero asymmetry A_μe^CPT = (P_μe − P_μ̅e̅)/(P_μe + P_μ̅e̅), computed here with exact three-flavour matrix-exponentiation propagators for T2K, NOνA, DUNE, and Hyper-Kamiokande; values range from 0.022 to 0.180 at the respective peak energies and differ by up to 9\% between normal and inverted mass orderings. The three-dimensional surface A_μe^CPT(E, δ_CP) at the DUNE baseline reveals an entanglement between extrinsic CPT violation and intrinsic CP violation in the high-L/E regime that requires joint statistical treatment. Concurrently, replacing the Preliminary Reference Earth Model (PREM) with a constant path-averaged density introduces a δ_CP-reconstruction bias below 0.3^∘ for L ≤ 5000 km but growing to 17.8^∘ at L = 7000 km and 172.2^∘ at L = 12000 km. Since both effects share the same matter-potential Hamiltonian they must be modelled jointly; a Poisson log-likelihood χ^2 statistic with nuisance-parameter pull terms is used to quantify the bias.
ER -