Double Chooz

Please see here for the official website

DC results as of Dec., 2012

Double Chooz is a long-baseline reactor neutrino oscillation experiment located at Chooz in France. The goal of this experiment is to search for the last parameter of the three-neutrino mixing matrix—previously assumed to be the smallest of the three mixing angles—by studying electron antineutrino disappearance. The measurement of this parameter can help us understand the underlying theory behind the standard model. It is also essential to determining the best design for future neutrino experiments, including DAEdALUS.

Double Chooz released its first result of the measuremnt of θ13 at the LowNu11 conference in November 2011, and the paper was accepted by PRL in March 2012. The results from the Daya Bay and RENO experiments, also measuring θ13, came out by summer 2012, and all results from the reactor and past accelerator experiments agreed within the errors very well. The updated result of the θ13 measurement from Double Chooz was also published in summer 2012 (above left plot) as a paper in PRD. We find sin213=0.109±0.030(stat)±0.025(syst).

While accumulating more statisics to gain a higher sensitivity to θ13, Double Chooz has expanded the physics interest to various subtopics, including the first study of Lorentz violation with reactor-based experiments, published in PRD, and a dedicated background analysis with reactor-off data, also published in PRD.

The latest news from the experiment is the first measurement of θ13 using neutron capture on hydrogen (above right plot). This analysis method, called hydrogen analysis, provides a data sample which is statistically independent from the sample obtained from the standard analysis method common to all reactor-based experiments; hence, the new method serves as an important confirmation of past measurements. The result was published in January 2013. The current goal is to perform a combined measurement of θ13 using the standard method and new approach using hydrogen, with higher statistics.

MIT and the Conrad group have been deeply involved in all aspects of the experiment. Our work includes the design and implementation of the environmental and voltage monitoring system; commissioning of the neutrino detector; and software development of the data production framework for data reconstruction, analysis, and Monte Carlo study. For higher-level physics analysis topics, we have been at the center of all published results. In particular, the Loretnz violation analysis and hydrogen analysis have been led by our group members from beginning to end.

Finally, the group led work in two areas applicable to a wider science community than neutrino physics. The first is the analysis of the DRAGON Monte Carlo simulation, a crucial part of neutrino flux prediction, in collaboration with the Lawrence Livermore National Laboratory. This result is applicable to nonproliferation studies. The second is the development of a genuine low-pressure gas neutron time projection chamber (TPC) detector prototype (read more in this paper) which is currently deployed in the Chooz laboratory and taking data. A larger-sized detector of this type will aim to measure the muon-induced spallation neturon flux at various depths underground. This measurement is expected to be of great interest to all collaborations working on low-energy underground physics experiments in the world.

Presently in the Conrad Double Chooz group: Josh Spitz (PD), Kazuhiro Terao (GS), and Xavier Hubbard (UG)

This page was updated January 2013