Abstract
The T2K experiment reports updated measurements of neutrino and antineutrino oscillations using both appearance and disappearance channels. This result comes from an exposure of $14.9~(16.4) \times 10^{20}$ protons on target in neutrino (antineutrino) mode. Significant improvements have been made to the neutrino interaction model and far detector reconstruction. An extensive set of simulated data studies have also been performed to quantify the effect interaction model uncertainties have on the T2K oscillation parameter sensitivity. T2K performs multiple oscillation analyses that present both frequentist and Bayesian intervals for the PMNS parameters. For fits including a constraint on \ssqthonethree from reactor data and assuming normal mass ordering T2K measures $\sin^2\theta_{23} = 0.53^{+0.03}_{-0.04}$ and $\Delta{}m^2_{32} = (2.45 \pm 0.07) \times 10^{-3}$ eV$^{2}$c$^{-4}$. The Bayesian analyses show a weak preference for normal mass ordering (89% posterior probability) and the upper $\sin^2\theta_{23}$ octant (80% posterior probability), with a uniform prior probability assumed in both cases. The T2K data exclude CP conservation in neutrino oscillations at the $2\sigma$ level.
Highlights
The neutrino interaction model used for this work is improved relative to Ref. [26], incorporating in-medium effects (RPA) and 2p2h shape uncertainties in the chargedcurrent zero-pion signal channel
A detailed set of simulated data studies were performed to assess the robustness of the analysis to alternative choices of neutrino interaction model
These studies demonstrated that the nucleon removal energy uncertainty can have a significant effect on the allowed regions for sin2 θ23 and Δm232 and, to a lesser extent, Δm232 was sensitive to all of the alternative models studied
Summary
The fact that neutrino flavor mixing [1] and oscillations [2] account for the apparent depletion of neutrino fluxes from natural sources is well established by detailed observations of these sources [3,4,5] and verified by. Experiments using monitored artificial sources [6,7,8]. Neutrino mixing requires that at least two of the neutrino masses (m1, m2 and m3) be nonzero, which in turn requires expanding upon the Standard Model. Masses require either new gauge singlets—right-handed neutrinos—or a different mass generation mechanism from other Standard Model fermions, or a combination of both.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
