2003/08/31 by Thomas Schwetz · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ex #hep-ph
paper · pdf · doi:10.1016/j.physletb.2003.10.024
published as Phys.Lett.B577:120-128,2003 · New figure added and discussion of results extended, version to appear in Phys. Lett. B, 14 pages, 5 figures
arxiv created 2003/10/21 · openalex publication_date 2003/11/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this letter the robustness of the first results from the KamLAND reactor neutrino experiment with respect to variations in the statistical analysis is considered. It is shown that an event-by-event based likelhood analysis provides a more powerful tool to extract information from the currently available data sample than a least-squares method based on energy binned data. Furthermore, a frequentist analysis of KamLAND data is performed. Confidence regions with correct coverage in the plane of the oscillation parameters are calculated by means of a Monte Carlo simulation. I find that the results of the usually adopted χ2-cut approximation are in reasonable agreement with the exact confidence regions, however, quantitative differences are detected. Finally, although the current data is consistent with an energy independent flux suppression, a ∼ 2σ indication in favour of oscillations can be stated, implying quantum mechanical interference over distances of the order of 200 km.