Confidence in the Mass Hierarchy Determination from Reactor Neutrino Experiments

Topical Research Meeting: Prospects in Neutrino Physics

Ciuffoli, E.^1 ; Evslin, J.^2 ; Zhang, X.M.^1

Institute of High Energy Physics (IHEP), CAS, Beijing

100049, China^1

Institute of Modern Physics, CAS, NanChangLu 509, Lanzhou

730000, China^2

关键词: Degree of freedom;    Energy response;    Mass hierarchy;    MC simulation;    Neutrino experiments;    Neutrino mass;    Non nested hypothesis;    Two-hierarchy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/598/1/012016/pdf
DOI  :  10.1088/1742-6596/598/1/012016

来源: IOP

【 摘 要 】

In the next decade, a number of experiments will attempt to determine the neutrino mass hierarchy. We will discuss some of the challenges that these experiments will face, focusing on the reactor neutrino experiments at intermediate baselines. Here, for example, even a small nonlinear energy response can severely affect the sensitivity to the hierarchy. Using MC simulations, we will show the probability of successfully determining the hierarchy for some realistic locations of the detector. We will also show that, since the two hierarchies are non-nested hypothesis, the statistic Δχ2does not follow a one-degree-of-freedom χ2distribution and hence the sensitivity to the hierarchy cannot be estimated by taking the square root of the expected Δχ2; we will present the correct formula for the sensitivity.