How sensitive is a neutrino factory to the angle θ13\theta_{13}?

We consider the impact of non-standard interactions of neutrinos (NSI) on the determination of neutrino mixing parameters at a neutrino factory using \pnu{e}\to\pnu{\mu} ``golden channels'' for the measurement of $\theta_{13}$. We show how a small residual NSI leads to a drastic loss in sensitivity in $\theta_{13}$, of up to two orders of magnitude. This can be somewhat overcome if two baselines are combined.Comment: 4 pages, 3 figure

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

Physics Potential of a 2540 Km Baseline Superbeam Experiment

We study the physics potential of a neutrino superbeam experiment with a 2540 km baseline. We assume a neutrino beam similar to the NuMI beam in medium energy configuration. We consider a 100 kton totally active scintillator detector at a 7 mr off-axis location. We find that such a configuration has outstanding hierarchy discriminating capability. In conjunction with the data from the present reactor neutrino experiments, it can determine the neutrino mass hierarchy at 3 sigma level in less than 5 years, if sin^2(2*theta13) > 0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5 year neutrino run and a 5 year anti-neutrino run, it can determine non-zero theta13 at 3 sigma level if sin^2(2*theta13) > 7*10^{-3} and hierarchy at 3 sigma level if sin^2(2*theta13) > 8*10^{-3}. This data can also distinguish deltaCP = pi/2 from the CP conserving values of 0 and pi, for sin^2(2*theta13) > 0.02.Comment: 16 pages, 7 figures and 1 table: Published versio

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

Identifying the Neutrino mass Ordering with INO and NOvA

The relatively large value of $\theta_{13}$ established recently by the Daya Bay reactor experiment opens the possibility to determine the neutrino mass ordering with experiments currently under construction. We investigate synergies between the NOvA long-baseline accelerator experiment with atmospheric neutrino data from the India-based Neutrino Observatory (INO). We identify the requirements on energy and direction reconstruction and detector mass for INO necessary for a significant sensitivity. If neutrino energy and direction reconstruction at the level of 10% and 10 degree can be achieved by INO a determination of the neutrino mass ordering seems possible around 2020.Comment: 18 pages, 8 figures, minor improvements and clarifications, new panel in fig. 7, version to appear in JHEP, typo in eq. 4 correcte

Where we are on θ13\theta_{13}: addendum to "Global neutrino data and recent reactor fluxes: status of three-flavour oscillation parameters"

In this addendum to arXiv:1103.0734 we consider the recent results from long-baseline $\nu_\mu\to\nu_e$ searches at the T2K and MINOS experiments and investigate their implications for the mixing angle $\theta_{13}$ and the leptonic Dirac CP phase $\delta$. By combining the $2.5\sigma$ indication for a non-zero value of $\theta_{13}$ coming from T2K data with global neutrino oscillation data we obtain a significance for $\theta_{13} > 0$ of about $3\sigma$ with best fit points $\sin^2\theta_{13} = 0.013(0.016)$ for normal (inverted) neutrino mass ordering. These results depend somewhat on assumptions concerning the analysis of reactor neutrino data.Comment: 5 pages, 2 figures and 1 tabl

Prospects of accelerator and reactor neutrino oscillation experiments for the coming ten years

We analyze the physics potential of long baseline neutrino oscillation experiments planned for the coming ten years, where the main focus is the sensitivity limit to the small mixing angle $\theta_{13}$. The discussed experiments include the conventional beam experiments MINOS, ICARUS, and OPERA, which are under construction, the planned superbeam experiments J-PARC to Super-Kamiokande and NuMI off-axis, as well as new reactor experiments with near and far detectors, represented by the Double-Chooz project. We perform a complete numerical simulation including systematics, correlations, and degeneracies on an equal footing for all experiments using the GLoBES software. After discussing the improvement of our knowledge on the atmospheric parameters $\theta_{23}$ and $\Delta m^2_{31}$ by these experiments, we investigate the potential to determine $\theta_{13}$ within the next ten years in detail. Furthermore, we show that under optimistic assumptions and for $\theta_{13}$ close to the current bound, even the next generation of experiments might provide some information on the Dirac CP phase and the type of the neutrino mass hierarchy.Comment: 38 pages, 13 figures, Eqs. (1) and (5) corrected, small corrections in Figs. 8, 9, and Tab. 4, discussion improved, ref. added, version to appear in PRD, high resolution figures are available at http://www.sns.ias.edu/~winter/figs0403068.htm

EURONU WP6 2009 yearly report: Update of the physics potential of Nufact, superbeams and betabeams

Many studies in the last ten years have shown that we can measure the unknown angle theta13, discover leptonic CP violation and determine the neutrino hierarchy in more precise neutrino oscillation experiments, searching for the subleading channel nue -> numu in the atmospheric range. In this first report of WP6 activities the following new results are reviewed: (1) Re-evaluation of the physics reach of the upcoming generation of experiments to measure theta13 and delta; (2) New tools to explore a larger parameter space as needed beyond the standard scenario; (3) Neutrino Factory: (a) evaluation of the physics reach of a Nufact regards sterile neutrinos; (b) evaluation of the physics reach of a Nufact as regards non-standard interactions; (c) evaluation of the physics reach of a Nufact as regards violation of unitarity; (d) critical assessment on long baseline tau-detection at Nufact; (e) new physics searches at a near detector in a Nufact; (4) Beta-beams: (a) choice of ions and location for a gamma = 100 CERN-based beta-beam; (b) re-evaluation of atmospheric neutrino background for the gamma = 100 beta-beam scenario; (c) study of a two baseline beta-beam; (d) measuring absolute neutrino mass with beta-beams; (e) progress on monochromatic beta-beams; (5) Update of the physics potential of the SPL super-beam. Eventually, we present an updated comparison of the sensitivity to theta13, delta and the neutrino mass hierarchy of several of the different proposed facilities.Comment: 2009 Yearly report of the Working Package 6 (Physics) of the EUROnu FP7 EU project. 55 pages, 21 figures

Non-Standard Neutrino Interactions from a Triplet Seesaw Model

We investigate non-standard neutrino interactions (NSIs) in the triplet seesaw model featuring non-trivial correlations between NSI parameters and neutrino masses and mixing parameters. We show that sizable NSIs can be generated as a consequence of a nearly degenerate neutrino mass spectrum. Thus, these NSIs could lead to quite significant signals of lepton flavor violating decays such as \mu^- \to e^- \nu_e anti\nu_\mu and \mu^+ \to e^+ anti\nu_e \nu_\mu at a future neutrino factory, effects adding to the uncertainty in determination of the Earth matter density profile, as well as characteristic patterns of the doubly charged Higgs decays observable at the Large Hadron Collider.Comment: 4 pages, 3 figures and 1 table; v2: minor corrections, Sect. IV revise

First hint for CP violation in neutrino oscillations from upcoming superbeam and reactor experiments

We compare the physics potential of the upcoming neutrino oscillation experiments Daya Bay, Double Chooz, NOvA, RENO, and T2K based on their anticipated nominal luminosities and schedules. After discussing the sensitivity to theta_{13} and the leading atmospheric parameters, we demonstrate that leptonic CP violation will hardly be measurable without upgrades of the T2K and NOvA proton drivers, even if theta_{13} is large. In the presence of the proton drivers, the fast track to hints for CP violation requires communication between the T2K and NOvA collaborations in terms of a mutual synchronization of their neutrino-antineutrino run plans. Even in that case, upgrades will only discover CP violation in a relatively small part of the parameter space at the 3 sigma confidence level, while 90% confidence level hints will most likely be obtained. Therefore, we conclude that a new facility will be required if the goal is to obtain a significant result with high probability.Comment: 27 pages, 12 figure