Double-Chooz: a search for Theta13

The Double-Chooz experiment goal is to search for a non-vanishing value of the Theta13 neutrino mixing angle. This is the last step to accomplish prior moving towards a new era of precision measurements in the lepton sector. The current best constraint on the third mixing angle comes from the CHOOZ reactor neutrino experiment $\sin(2\theta_{13})^{2}<0.2$ (90% C.L., $\Delta m_{atm}^{2}=2.0$ eV$^{2}$). Double-Chooz will explore the range of $\sin(2\theta_{13})^{2}$ from 0.2 to 0.03-0.02, within three years of data taking. The improvement of the CHOOZ result requires an increase in the statistics, a reduction of the systematic error below one percent, and a careful control of the backgrounds. Therefore, Double-Chooz will use two identical detectors, one at 150 m and another at 1.05 km distance from the Chooz nuclear cores. In addition, we will to use the near detector as a ``state of the art'' prototype to investigate the potential of neutrinos for monitoring the civil nuclear power plants. The plan is to start operation with two detectors in 2008, and to reach a sensitivity sin$^{2}$$(2\theta_{13})$ of 0.05 in 2009, and 0.03-0.02 in 2011.Comment: 3 pages, 1 figure, Proceedings of Nufact'04, July 26 - August 01 2004, Osak

What is the probability that θ13\theta_{13} and CP violation will be discovered in future neutrino oscillation experiments?

The sensitivity of future neutrino oscillation experiments is determined within a frequentist framework by using a statistical procedure based on Monte Carlo simulations. I consider the search for a non-zero value of the mixing angle $\theta_{13}$ at the T2K and Double-Chooz experiments, as well as the discovery of CP violation at the example of the T2HK experiment. The probability that a discovery will be made at a given confidence level is calculated as a function of the true parameter values by generating large ensembles of artificial experiments. The interpretation of the commonly used sensitivity limits is clarified.Comment: 11 pages, 5 figure

Quark mixing in the discrete dark matter model

We consider a model in which dark matter is stable as it is charged under a Z2 symmetry that is residual after an A4 flavour symmetry is broken. We consider the possibility to generate the quark masses by charging the quarks appropriately under A4. We find that it is possible to generate the CKM mixing matrix by an interplay of renormalisable and dimension-six operators. In this set-up, we predict the third neutrino mixing angle to be large and the dark matter relic density to be in the correct range. However, low energy observables - in particular meson-antimeson oscillations - strongly limit the available parameter space.Comment: 10 pages, 4 figures; version 3 as appeared in Nuclear Physics

Combined potential of future long-baseline and reactor experiments

We investigate the determination of neutrino oscillation parameters by experiments within the next ten years. The potential of conventional beam experiments (MINOS, ICARUS, OPERA), superbeam experiments (T2K, NOvA), and reactor experiments (D-CHOOZ) to improve the precision on the ``atmospheric'' parameters $\Delta m^2_{31}$, $\theta_{23}$, as well as the sensitivity to $\theta_{13}$ are discussed. Further, we comment on the possibility to determine the leptonic CP-phase and the neutrino mass hierarchy if $\theta_{13}$ turns out to be large.Comment: 4 pages, 4 figures, Talk given by T.S. at the NOW2004 workshop, Conca Specchiulla (Otranto, Italy), 11--17 Sept. 200

Experimental tests for the Babu-Zee two-loop model of Majorana neutrino masses

The smallness of the observed neutrino masses might have a radiative origin. Here we revisit a specific two-loop model of neutrino mass, independently proposed by Babu and Zee. We point out that current constraints from neutrino data can be used to derive strict lower limits on the branching ratio of flavour changing charged lepton decays, such as $\mu \to e \gamma$. Non-observation of Br($\mu \to e \gamma$) at the level of $10^{-13}$ would rule out singly charged scalar masses smaller than 590 GeV (5.04 TeV) in case of normal (inverse) neutrino mass hierarchy. Conversely, decay branching ratios of the non-standard scalars of the model can be fixed by the measured neutrino angles (and mass scale). Thus, if the scalars of the model are light enough to be produced at the LHC or ILC, measuring their decay properties would serve as a direct test of the model as the origin of neutrino masses.Comment: 14 pages, 16 figure

From Double Chooz to Triple Chooz - Neutrino Physics at the Chooz Reactor Complex

We discuss the potential of the proposed Double Chooz reactor experiment to measure the neutrino mixing angle $\sin^2 2\theta_{13}$. We especially consider systematical uncertainties and their partial cancellation in a near and far detector operation, and we discuss implications of a delayed near detector startup. Furthermore, we introduce Triple Chooz, which is a possible upgrade scenario assuming a second, larger far detector, which could start data taking in an existing cavern five years after the first far detector. We review the role of the Chooz reactor experiments in the global context of future neutrino beam experiments. We find that both Double Chooz and Triple Chooz can play a leading role in the search for a finite value of $\sin^2 2\theta_{13}$. Double Chooz could achieve a sensitivity limit of $\sim 2 \cdot 10^{-2}$ at the 90%~confidence level after 5~years while the Triple Chooz setup could give a sensitivity below $10^{-2}$.Comment: 18 pages, 6 figure

Reactor Monitoring with Neutrinos

The fundamental knowledge on neutrinos acquired in the recent years open the possibility of applied neutrino physics. Among it the automatic and non intrusive monitoring of nuclear reactor by its antineutrino signal could be very valuable to IAEA in charge of the control of nuclear power plants. Several efforts worldwide have already started.Comment: 5 pages - XXII International Conference On Neutrino Physics And Astrophysics (Neutrino 2006

Chasing θ13\theta_{13} with new reactor neutrino experiments

It is now widely accepted that a new middle baseline disappearance reactor neutrino experiment with multiple detectors could provide a clean measurement of the $\theta_{13}$ mixing angle, free from any parameter degeneracies and correlations induced by matter effect and the unknown leptonic Dirac CP phase. The current best constraint on the third mixing angle comes from the Chooz reactor neutrino experiment $\sin^{2}(2\theta_{13})<0.2$ (90$$ C.L., $\Delta m_{\rm atm}^{2}=2.0 10^{-3}$ eV$^{2}$). Several projects of experiment, with different timescales, have been proposed over the last two years all around the world. Their sensitivities range from $\sin^{2}(2\theta_{13})<$ 0.01 to 0.03, having thus an excellent discovery potential of the $\nu_e$ fraction of $\nu_3$.Comment: Talk given at the 6th International Workshop on Neutrino Factories & Superbeams, July 26-Aug 1, 2004, Osaka, Japan. 5 page

Neutrino Factory Superbeam

We discuss the optimization of a neutrino factory for large \sin^2 2 \theta_{13}, where we assume minimum effort on the accelerator side. This implies that we use low muon energies for the price of an optimized detection system. We demonstrate that such a neutrino factory performs excellent if combined with the electron neutrino appearance channel. Instead of the platinum channel operated with the muon neutrinos from the muon decays, we propose to use the initial superbeam from the decaying pions and kaons, which might be utilized at little extra effort. Since we assume out-of-phase bunches arriving at the same detector, we do not require electron charge identification. In addition, we can choose the proton energy such that we obtain a synergistic spectrum peaking at lower energies. We find that both the superbeam and the neutrino factory beam should used at the identical baseline to reduce matter density uncertainties, possibly with the same detector. This effectively makes the configuration a single experiment, which we call ``neutrino factory superbeam''. We demonstrate that this experiment outperforms a low-energy neutrino factory or a wide band beam alone beyond a simple addition of statistics.Comment: 7 pages, 5 figures, 1 tabl

R2D2 - a symmetric measurement of reactor neutrinos free of systematical errors

We discuss a symmetric setup for a reactor neutrino oscillation experiment consisting of two reactors separated by about 1 km, and two symmetrically placed detectors, one close to each reactor. We show that such a configuration allows a determination of $\sin^22\theta_{13}$ which is essentially free of systematical errors, if it is possible to separate the contributions of the two reactors in each detector sufficiently. This can be achieved either by considering data when in an alternating way only one reactor is running or by directional sensitivity obtained from the neutron displacement in the detector.Comment: 11 pages, 3 figures, clarifications added, some numbers in relation with the neutron displacement corrected, version to appear in JHE