Confidence regions for neutrino oscillation parameters from double-Chooz data

Abstract

In this work, an independent and detailed statistical analysis of the double-Chooz experiment is performed. In order to have a thorough understanding of the implications of the double-Chooz data on both oscillation parameters sin 2 ð2θ 13 Þ and Δm −0.215 × 10 −3 eV 2 =c 4 . Our analysis allows us to study the effects of the so-called "spectral bump" around 5 MeV; it is observed that a variation of this spectral bump may be able to move the Δm 2 31 best fit value, in such a way that Δm 2 31 takes the order of magnitude of the MINOS value. In other words, if we allow the variation of the spectral bump, then we may be able to determine both oscillation parameters using Far detector data only, with no further restrictions from other experiments. Finally, and with the intention of understanding the effects of the preliminary Near detector data, we performed two different analyses, aiming to eliminate the effects of the energy bump. As a consequence, it is found that unlike the Far detector analysis, the Near detector data may be able to fully determine both oscillation parameters by itself, resulting in sin 2 ð2θ 13 Þ ¼ 0.095 AE 0.053 and Δm