CP violation and matter effect in long-baseline neutrino oscillation in the four-neutrino model

Abstract

We investigate the CP violation effect and the matter effect in the long-baseline neutrino oscillations in the four-neutrino model with mass scheme of the two pairs of two close masses separated by a gap of the order of 1 eV by using the constraints on the mixing matrix derived from the solar neutrino deficit, atmospheric neutrino anomaly, LSND experiments, and the other terrestrial neutrino oscillation experiments. We also use the results of the combined analyses by Gonzalez-Garcia, Maltoni, and Peña-Garay of the solutions to the solar and atmospheric neutrino problems with the recent SNO solar neutrino data. For the solution of close-to-active solar neutrino oscillations plus close-to-sterile atmospheric neutrino oscillations, the pure CP violation part of the oscillation probability difference between the CP-conjugate channels could attain as large as $0.10-0.25$ in the neutrino energy range of $E=6-15$ GeV at the baseline $L=730$ km for ${\nu }_{\mu }\to {\nu }_{\tau }$ oscillation, and the matter effect is at the $8-15$ level of the pure CP violation effect, while for the solution of near-pure-sterile solar neutrino oscillations plus near-pure-active atmospheric neutrino oscillations, the pure CP violation effect in $\Delta P({\nu }_{\mu }\to {\nu }_{\tau })$ is very small $(\sim 0.01)$ and is comparable to the matter effect. For ${\nu }_{\mu }\to {\nu }_e$ oscillation, the pure CP violation effect is independent of the active-sterile admixture and is at most 0.05 in $E=1.5-3$ GeV at $L=290$ km and the matter effect is at the $15-30$ level.

29 pages, 12 eps figures. We have shown the dependence of the CP violation effects on various parameters, discussed about the relation between the active-sterile neutrino admixture and the effects in both Tables and Figures, and added some references to the published works

References in corpus (15)

• Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory
• Solar 8B and hep Neutrino Measurements from 1258 Days of Super-Kamiokande Data
• Constraints on Neutrino Oscillations Using 1258 Days of Super-Kamiokande Solar Neutrino Data
• Observation of Large CP Violation in the Neutral B Meson System
• Observation of CP violation in the B^0 meson system
• Global Analysis of Solar Neutrino Oscillations Including SNO CC Measurement
• Model-dependent and independent implications of the first Sudbury Neutrino Observatory results
• Unknowns after the SNO Charged-Current Measurement
• Impact of the first SNO results on Neutrino Mass and Mixing
• 4-Neutrino mass schemes and the likelihood of (3+1)-mass spectra
• Solar and Atmospheric Four-Neutrino Oscillations
• CP violation effects and high energy neutrinos
• The matter effect to T-violation at a neutrino factory
• The 2+2 and 3+1 Four-Family Neutrino Mixing at the Neutrino Factory
• Vacuum mimicking phenomena in neutrino oscillations

Cited by in corpus (4)

• Identifying neutrinos and antineutrinos in neutral-current scattering reactions
• Can One Distinguish Tau Neutrinos from Antineutrinos in Neutral-Current Pion Production Processes?
• Spin-dependent neutrino-induced nucleon knockout
• Modeling realistic Earth matter density for CP violation in neutrino oscillation