Global analysis of three-flavor neutrino masses and mixings

TL;DR

This work provides a comprehensive, state-of-the-art (as of 2005) global analysis of neutrino masses and mixings within the three-flavor framework, integrating solar, atmospheric, reactor, and accelerator data with non-oscillation mass probes. It demonstrates a consistent LMA solution for solar neutrinos, strongly supports matter effects in the Sun, and constrains the mixing angles and mass splittings with precise Δm^2 and θ12 values, while allowing a small but nonzero θ13. The study also maps oscillation parameters onto absolute mass observables (mβ, mββ, Σ) and exposes tensions between oscillation data and non-oscillation bounds, notably involving the controversial 0νββ signal and cosmological Σ limits. The findings establish a critical baseline for future experiments aiming to resolve the absolute neutrino mass scale and potential CP-violation in the lepton sector, as well as for testing the robustness of the standard three-neutrino paradigm.

Abstract

We present a comprehensive phenomenological analysis of a vast amount of data from neutrino flavor oscillation and non-oscillation searches, performed within the standard scenario with three massive and mixed neutrinos, and with particular attention to subleading effects. The detailed results discussed in this review represent a state-of-the-art, accurate and up-to-date (as of August 2005) estimate of the three-neutrino mass-mixing parameters.

Figures (32)

• Figure 1: Regions separately allowed by the Chlorine (Cl), Gallium (Ga), Super-Kamiokande (SK) and Sudbury Neutrino Observatory (SNO) experiments at the $2\sigma$ level ($\Delta\chi^2=4$) in the $(\delta m^2,\tan^2\theta_{12})$ plane, for $\theta_{13}=0$. The LMA region allowed at $2\sigma$ by the Cl+Ga+SK+SNO combination is superposed in each panel.
• Figure 2: Neutrino potential $V=\sqrt{2}\,G_FN_e$ as a function of the normalized radius in the Sun. Also shown are the radial production regions for $^8$B, $^7$Be, and pp solar neutrinos (in arbitrary vertical scale). The curves refer to the Bahcall-Serenelli 2005 standard solar model.
• Figure 3: The energy profile of the solar $\nu_e$ survival probability $P_{ee}$ for best-fit LMA values and $\theta_{13}=0$. The function $P_{ee}(E)$ shows a smooth transition from vacuum to matter-dominated regime as $E$ increases, with some differences induced by averaging over different production regions (for $^8$B, $^7$Be and pp neutrinos) and, to a smaller extent, by nighttime (N) Earth effects with respect to daytime (D). Also shown are the corresponding solar neutrino energy spectra (in arbitrary vertical scale).
• Figure 4: KamLAND constraints in the mass-mixing plane $(\delta m^2,\sin^2\theta_{12})$ and for $\theta_{13}=0$, as derived by an unbinned maximum-likelihood analysis of the total rate, spectrum shape, and rate+shape information. Contours are shown at 1, 2, and $3\sigma$ level.
• Figure 5: Solar and KamLAND constraints in the mass-mixing plane $(\delta m^2,\sin^2\theta_{12})$ and for $\theta_{13}=0$, shown both separately and in combination, at 1, 2, and $3\sigma$ level.