Can four neutrinos explain global oscillation data including LSND and cosmology?

TL;DR

This paper analyzes whether four-neutrino models can explain all neutrino oscillation data, including recent cosmological observations, and finds significant constraints on these models based on experimental and cosmological evidence.

Contribution

The study provides a comprehensive analysis of four-neutrino mass schemes in light of global oscillation and cosmological data, ruling out certain models and constraining others.

Findings

(2+2) schemes are ruled out by oscillation data

(3+1) schemes are disfavored by short-baseline experiments

Cosmological data further restrict (3+1) parameter space

Abstract

We present an analysis of the global neutrino oscillation data in terms of four-neutrino mass schemes. We find that the strong preference of oscillations into active neutrinos implied by solar+KamLAND as well as atmospheric neutrino data allows to rule out (2+2) mass schemes, whereas (3+1) schemes are strongly disfavoured by short-baseline experiments. In addition, we perform an analysis using recent data from cosmology, including CMB data from WMAP and data from 2dFGRS large scale structure surveys. These data lead to further restrictions of the allowed regions for the (3+1) mass scheme.