Disentangling genuine from matter-induced CP violation in neutrino oscillations

Abstract

We prove that, in any flavor transition, neutrino oscillation CP violating asymmetries in matter have two disentangled components: i) a CPT-odd T-invariant term, non-vanishing iff there are interactions with matter; ii) a T-odd CPT-invariant term, non-vanishing iff there is genuine CP violation. As function of the baseline, these two terms are distinct L-even and L-odd observables to separately test (i) matter effects sensitive to the neutrino hierarchy and (ii) genuine CP violation in the neutrino sector. For the golden ${\nu }_{\mu }\to {\nu }_e$ channel, the different energy distributions of the two components provide a signature of their separation. At long baselines, they show oscillations in the low energy region, with zeros at different positions and peculiar behavior around the zeros. We discover a magic energy $E=(0.91\pm 0.01)$ GeV at L = 1300 km with vanishing CPT-odd term and maximal genuine CP asymmetry proportional to $\sin \delta$, with $\delta$ the weak CP phase. For energies above 1.5 GeV, the sign of the CP asymmetry discriminates the neutrino hierarchy.

5 pages, 4 figures

References in corpus (10)

• Observation of electron-antineutrino disappearance at Daya Bay
• Indication of Electron Neutrino Appearance from an Accelerator-produced Off-axis Muon Neutrino Beam
• Measurement of Neutrino Oscillation by the K2K Experiment
• Status of neutrino oscillations 2018: first hint for normal mass ordering and improved CP sensitivity
• Updated fit to three neutrino mixing: exploring the accelerator-reactor complementarity
• Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF
• Compact Perturbative Expressions For Neutrino Oscillations in Matter
• Neutrino oscillograms of the Earth: effects of 1-2 mixing and CP-violation
• Neutrino oscillations at DUNE with improved energy reconstruction
• Probing the leptonic Dirac CP-violating phase in neutrino oscillation experiments

Cited by in corpus (8)

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• Do T asymmetries for neutrino oscillations in uniform matter have a CP-even component?
• The ESSnuSB design study: overview and future prospects
• A plethora of long-range neutrino interactions probed by DUNE and T2HK
• Analytical description of CP violation in oscillations of atmospheric neutrinos traversing the Earth
• The Aharonov-Bohm effect for a constant scalar matter potential in neutrino flavour interferometry
• Disentangling genuine from matter-induced CP violation in neutrino oscillations