Current unknowns in the three-neutrino framework

Abstract

We present an up-to-date global analysis of data coming from neutrino oscillation and nonoscillation experiments, as available in April 2018, within the standard framework including three massive and mixed neutrinos. We discuss in detail the status of the three-neutrino (3ν) mass-mixing parameters, both known and unknown. Concerning the latter, we find that: normal ordering (NO) is favored over inverted ordering (IO) at 3σ level; the Dirac CP phase is constrained within ∼ 15% (∼ 9%) uncertainty in NO (IO) around nearly-maximal CP-violating values; the octant of the largest mixing angle and the absolute neutrino masses remain undetermined. We briefly comment on other unknowns related to theoretical and experimental uncertainties (within 3ν) or possible new states and interactions (beyond 3ν).

Why matter effects matter for JUNO

“…where ∆ m 2 ee ≡ ∆m 2 ee (cos 2θ 13 − a/∆m 2 ee ) 2 + sin 2 2θ 13 , (8) and then θ 12 and ∆ m 2 21 cos 2 θ 12 ∆m 2 21 cos 2θ 12 − a ∆ m 2 21 ,…”

“…True (input) parameter values assumed in throughout this work unless otherwise stated. The oscillation parameters values and their errors were taken from ref [8]…”

Distinguishing between the twin b-flavored unitarity triangles on a circular arc

“…To illustrate, we plot each pair of the rescaled PMNS unitarity triangles in the complex plane in Figures 4-6 and calculate not only the center and radius of the circular arc on which they are located but also their common inner angle in Table 1 by using the best-fit values of three neutrino mixing angles (θ 12 , θ 13 and θ 23 ) and the Dirac CP-violating phase (δ) [32,33], where both the normal neutrino mass ordering (NMO) and the inverted mass ordering (IMO) are taken into account. We admit that for the time being the large uncertainty associated with δ prevents us from establishing the leptonic unitarity triangles in a reliable way [34,35], but Figures 4-6 and Table 1 do give one a ball-park feeling of some salient features of unitarity triangles in the lepton sector.…”

“…Numerical results for the center O and radius R of a circular arc on which each pair of the PMNS unitarity triangles are located, and those for their common inner angle α i (for i = 1, 2, 3) defined in Eq (28). in the NMO or IMO case, where the best-fit values of three neutrino mixing angles and the Dirac CP-violating phase[32,33] have been input.…”

Exploring NSI degeneracies in long-baseline experiments

“…Most of the Standard Model parameters in the leptonic sector have been measured with high precision, including most of the mixing angles of the Pontecorvo-MakiNakagawa-Sakata matrix [1][2][3][4] and the charged lepton masses [5]. It is expected that DUNE [6][7][8][9] and HyperKamiokande [10,11] will accurately measure the CP violating phase, δ, if we restrict to the standard three neutrino oscillation picture.…”