Determination of the θ23 octant in long baseline neutrino experiments within and beyond the standard model

Abstract

The recent data indicate that the neutrino mixing angle θ 23 deviates from the maximal-mixing value of 45°, showing two nearly degenerate solutions, one in the lower octant (LO) (θ 23 < 45°) and one in the higher octant (HO) (θ 23 > 45°). We investigate, using numerical simulations, the prospects for determining the octant of θ 23 in the future long baseline oscillation experiments. We present our results as contour plots on the (θ 23 − 45°, δ)-plane, where δ is the CP phase, showing the true values of θ 23 for which the octant can be experimentally determined at 3σ, 2σ and 1σ confidence level. In particular, we study the impact of the possible nonunitarity of neutrino mixing on the experimental determination of θ 23 in those experiments.

Matter density profile shape effects at DUNE

“…These impacts have been well-studied for several decades [2] and are critical for the physics goals of the experiment (See, e.g., Refs. [3][4][5][6][7][8][9]). However, recent discussion has arisen over how well-known the Earth's matter density is known, and whether this uncertainty can impact the ability of DUNE to perform its experimental goals [10].…”

Probability Thermodynamics and Probability Quantum Field

“…The chi-squared distribution (χ 2 -distribution) is the distribution of a sum of the squares of standard normal random variables. The chi-square distribution appears in neutrino experiments [24], measurements of microwave background [25], and statistical inference [20,26].…”

Beyond Standard Neutrino Theory

“…A serious problem here is, since the fit is not bad (the χ 2 is reasonably small), the result looks consistent with the standard oscillation scenario, and therefore, we cannot tell if we have exotic effects or not. NSIs also affect the determination of the octant of the 2-3 mixing angle [5,14,15]; See the right plot in Fig. 2 [5].…”